94 Ranger 2.3L Misfire – poor idle and very poor acceleration


gcaiola

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Suddenly began running rough on drive home from work, but while i was idling, talking to a neighbor. Idles poorly but does not stall or backfire. Starts consistently but accelerates so poorly it can’t be driven safely.
I popped the hood and noticed a vacuum hose that should connect to EVAP canister was completely off due to rubber boot dry-rotting. I have no idea how long it may have been disconnected. It’s a pre-formed black plastic tube, with custom bends, that connects evap canister to somewhere under throttle body, on firewall side. I can’t see it’s connection on the throttle end but it “seems” to be secured on the throttle body end, when I give it a light tug.

More details:
- A mechanical knocking or vibrating sound seems to come from underside of engine—or at least that’s where I hear it.
- Liquid drips from exhaust pipe –seems to be water
- After it idles for a few minutes (or less), when I turn it off, I can hear “fast dripping” sound in/near engine area for the next 15-30 seconds—like liquid is dripping somewhere. But nothing is dripping on the ground—so that is internal to something. (or maybe that sound has always been there and I never noticed)
- I have never changed vacuum hoses on this car. So it’s possible the rubber hoses are due to break down soon—although most look pretty good.

What I have done:
- No check engine light or diag codes come up
- Reinstalled air hose back in place on the evap canister side. Note I did not do a thorough check on this tube at other end, because I can’t see back below the throttle body where connects. I probably need to give this more attention but have been distracted due to other things below.

- Put a timing light on each plug wire, right off the coils. I did not check actual timing, just watched light pulses to check for anything unusual. The coilpack near front of car triggers light on/off consistently--checked all 4 wires. The coilpack behind it (nearest firewall) seems to pulse much quicker and slightly erratic. Along with that it seems the timing light pulses more dimly from all 4 of those wires (passenger side plugs of engine block), and I can see the light off (“missing”) occasionally. I tried to catch this on video but digital video loses some of this activity. Should the timing light look same for all plug wires, and on both coil packs?
- Removed all plug wires from both coil pack side, and checked resistance on both coils packs. Looks good across both pairs for each coil pack.
- I assumed that timing signals should be similar on both coil packs and since coil packs seemed ok, I replaced Ignition Module without doing a full diagnosis—hoping for an easy fix. Did not fix.
- Installed vacuum gauge. With engine idling, needle bounces VERY quickly between 14-17 inches. Read online this could be caused by stuck valve. But since this engine fires plugs on exhaust stroke also, I am guessing it could be any normal plug or plug wire problem on any 1 cylinder. Is that correct?

Between the vacuum reading and the funky timing light difference on rearmost coilpack (vs frontmost), I don’t know if I should be chasing a possible vacuum leak or an electrical issue that might be causing me to see the vacuum needle bounce. And because of the unusual timing light signal from the rearmost coil pack (on ALL its plug wire outputs), I assumed it could not be simply a single plug or wire. Am I over-complicating this?

I would appreciate any suggestions.
 


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tomw

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The liquid from the exhaust is normal. H2O is a byproduct of combustion.
The dripping after shutdown is normal, the oil from the cylinder head making its way back to the oilpan.
Check the resistance of your spark plug wires. There's a rule of thumb that I don't remember, XK ohms per foot. You will see those that are 'open' while those with continuity will show ohms in the K range. Open is bad.
The spark plugs on the drivers side work when the computer tells them to. Not all the time.
If repairing/replacing the vacuum line connection fixed the idle, I do not know what the current problem is...
tom
 

gcaiola

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Thanks for feedback, tomw. I won't be able to look troubleshoot again til this weekend. But til then, I have 1 main question based on your comments:

I get what you're saying about the spark plug wires. And it has been about 50K miles since I changed plugs and wires last, so they are due. But since ALL wires on the "backside" coil pack show exact same timing sequence as each other (and non-standard versus frontmost coil pack wires), I assumed the problem must be UPSTREAM of the wires. So I figured it was narrowed down to either rear coil pack, ignition module, ECM/PCM, or some related electrical connection between those. Is it possible that only one spark plug or wire is bad, but cause timing light to show same "misfire" sequence across all wires extending from that rear coilpack?

If you can let me know what you think about above question, I'll be ready to dig in this weekend. If you still think one plug could cause that symptom, I'll just plan to replace all plugs and wires. I will likely damage 1 or more wires trying to pull them to check resistance anyway, based on their age (brittle insulation), and how hard some may be to access at the plug end.



And less important but a few additional comments based on your feedback:
- Replacing the vacuum line did not fix. No noticeable change there.
- I didn't realize "dripping" sound was normal after turning engine off. Surprised I never noticed it as this has been my daily driver for at least a dozen years now. But glad to hear that.
- The H2O from exhaust is so extensive it has left rust stains on end of inner tailpipe and was much more than I expected. But maybe that is increased due to whatever is causing the misfire issue. Or maybe since I am only running the car for a few minutes at a time while trying to diagnose, more condensation exists, and doesn't have time to fully dry out the exhaust line.

thanks again!
 

tomw

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Remember that the plugs fire in pairs. 1&4, 2&3. The 'outer' two, and the 'inner' two both fire at the same time. If the wires are not plugged into the coil the 'same way' as the passenger side coil, that could cause problems when the drivers side was enabled.
If you have misfire on 1 or 4, likely both will misfire, as the spark has to go through both to ground, same for 2 & 3. I do not have one to fiddle with, so have limited knowledge.
Might be worthwhile to read up on how the thing works.
tom
 

gcaiola

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OK. Before changing plugs, I swapped the coil packs, just to be sure that wasn't cause of the problem and it was not. So I replaced the plugs. All looked normal EXCEPT for both at cyl 3 (3rd from front of car). Those were fouled more than all others. The passenger side of cyl 3 plug was dark and dirtied and the driver side cyl 3 plug was even worse--with wet oil on it.

An image of plugs is attached here (if this link works through the forum):
https://photos.app.goo.gl/5CSuVV6uyh4ycLwe9

Based on this, I didn't even put the plug wires back on yet. And after a few minutes of internet searching, I suspect maybe valve cover gasket needs replacement.

Is there a simple way to get more confidence that is the problem, before replacing it? For example, any way to tighten the bolts that hold valve cover on, just to see if that improves it, or maybe gains me a couple of weeks until a more convenient time to fix?

Also, I looked it up on rockauto.com and see 2 gaskets whose shapes look different. I'd hate to order the wrong part. Both of those attached here:
https://photos.app.goo.gl/x5o7gs4v2oEjDogV7
https://photos.app.goo.gl/j3kNNDGhmJU2LcGb6


If you agree or have other thoughts/experience, I'd love to hear them. Thanks again.
 
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tomw

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From the pic, it appears that #3 passenger side has some 'stuff' between the side electrode and the center electrode. A clearer picture might tell. It does appear pily, which would/could lead to misfire.


Did you check the continuity(ohms) of the spark plug wires?

Replacing a fouled plug will make/allow it to fire for a while, but if the wire is damaged, it will likely get fouled again.
If the misfire is due to oil fouling, it has two general sources. Valve stem seals, and piston rings. If the engine has a tendency to produce a puff of blue smoke out the exhaust when you accelerate after sitting at idle for a minute or so, then valve stem seals are a good candidate. If you get blue smoke out the tailpipe a lot of the time, then oil control ring failure is more likely.
Some consumption is normal, so don't worry about that.
The two gasket sets are for the same application. The blue gasket will change its shape as it is draped over the cam bearing support at the front of the camshaft. The 'wide' part will narrow down as the gasket hangs down the side of the cam tower.
The black fully formed gasket is already 'drooped' to fit onto the sides of the cam tower. It may be easier to install, I do not know. I have one in the basement awaiting install, but am considering looking for an 89-94 cam & followers to fit my 85 before installation. The rubber gaskets are designed for permanent use, and can be uninstalled and re-used without problem - they say.
The picture of the blue gasket is 'splayed' so you can see its shape. As the angled sides pull in, they'll conform to the straight line of the gasket surface on the head.
tom
 

gcaiola

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Good info on gaskets. I looked further at my Haynes manual and understand exactly what you are saying.

I didn't see anything between side and center electrode on the #3 cyl (passenger side) plug. Poor focus in prev pic. Here's a better pic of that plug:
https://photos.app.goo.gl/Ur47EQ9NDZM1qqrMA

That one was dry. I just noted the ceramic around the center electrode was fully dark/sooty, instead of light/white, like the same area on plugs for all other cylinders. The threads of that same plug have some kinda goo on them. I assume that was from me doing a poor job of anti-seize several years ago, but I don't know. Since it is on threads only, I assume it has nothing to do with internals of engine.

Unlike passenger side #3, the driver's side #3 plug was wet with oil--even though I have only idled this car for a few minutes total in past 2 months.

I ohmed the first four of wires I removed--all on passenger side. If I remember right, the #3 pass. side was like 5.6k ohms. Resistance seemed normal in reference to the others on that side, based on wire length--ranging from maybe 2.6k to 6.7k ohms from shortest to longest if I remember correctly.

I do need to ohm the drivers side plug wires--especially #3. I guess there would be no oil on plug like that caused by just a plug or plug wire issue, would it? And there is absolutely no blue smoke from exhaust--I have seen that on this car. I guess that's good. But it confuses me to how there was oil all over the 1 plug like that.

So i will check resistance of the #3 driver's side plug wire. But unsure how oily plug could be related to that.

Any thoughts on all my rambling?
 
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tomw

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I think you make good sense. I would check the #3 drivers side wire as you plan. If damaged, the plug may not fire, and could get coated with whatever is in the combustion chamber.
Is it possible the cam cover gasket allowed oil to gather on #3 drivers side? It could then flow down as the plug is removed from the last threads.

Did the idle improve after repairing the hose connection? What is it doing now after replacing the plugs?
Did this happen 'all at once', such that you drove off in the AM running fine, but by PM it was merde? When that happens, most times it will be electrical or electronic. Valves, rings, etc take time to fail, and degrade more slowly. Injectors can get plugged, but you would also note some loss of power when going highway speed.
Is if misfiring all the time? At idle only? Upon acceleration? Have you checked fuel pressure and delivery volume? Is the air filter plugged or relatively OK? Is the PCV system in proper condition? The PCV valve meters air into the intake in addition to what comes past the throttle plate. If something is goofy, the computer won't know, and may diddle with the fuel spritz time. Do you have a MAP sensor? It is about the size of a pack of cigarettes, and has a vacuum line direct to the intake, along with an electrical connector. If it goes nutz, you idle will/can go to pieces and be very erratic. It measures manifold vacuum to determine load on the engine. If you have a MAF you likely no longer have the MAP. Manifold Absolute Pressure - similar to a barometer.
tom
 

gcaiola

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Cyl Pass Driver
# __Side__Side
1 - 4.03k 8.26k
2 - 4.96k 7.97k
3 - 6.21k 9.33k
4 - 7.28k 9.07k

Nothing seems far out of ordinary. And I don't think any of that would cause oil on that plug.

Regarding your questions:
-Idle never improved after replacing hose.
-It definitely happened all-at-once. Drove home from work completely fine. I idled (all fine) for about 1 min to stop and speak to a neighbor on my street. As I said goodbye to neighbor, tried to accelerate gently to drive the last 100 ft home, it instantly happened. The exhaust became about twice as loud and rough sounding, and acceleration became very difficult too.
-It is misfiring ALL THE TIME--idle or attempted acceleration (didn't have much HP to begin with, now it's really slow going).

-Have not checked fuel pressure, air filter, or PCV valve. I checked fuel pressure a few months earlier as a sanity check when working on another car. It was fine then. I doubt any of those is the problem, although I will check PCV and air filter. I returned my fuel pressure loaner tool so may not do that again.
-I have a MAF. Didn't check it for this issue. But tending to think it's unrelated here due to other things seen.

- Since I am 99% certain there's something affecting cylinder #3, and that I fixed nothing based on replacing plugs only, I didn't even put plug wires back on. Figured:
1) I'd be buying new ones and would rather install once (due to driver side being hard to reach)
2) I haven't fixed any problem so I don't think I am going to see any improvement
3) Figured the next step *may* be replacing valve cover gasket. I may not need to remove plug wires for that but seemed easier to leave them out of the way.

Between the #3 plugs and small amount of oily residue at seam where valve cover gasket is--especially on back side of block, plus 3 minute internet search, I guessed that gasket is the cause. I have zero experience to be confident of that, of course.

- To your other comment....is valve cover gasket the same as what you called "cam cover gasket"? I know little about this stuff--never changed one. Mostly don't go beyond brakes/rotors, plugs/plug wires, a water pump here and there, a timing belt once--but never anything WITHIN engine.

And unless something turns up with PCV, air filter, etc checks you mentioned, I think I am looking at valve cover replacement. I have never done anything WITHIN engine before. So while that cover is off, is there anything else I should plan to clean, replace when I am already in there? I'd rather buy parts upfront and plan for it.
 
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tomw

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Something that seems to happen that quickly is generally a failure of non-mechanical nature. A valve, rings, cam, lifter, etc generally start by showing some symptoms before causing dead cylinder misfire.
One of the more auxiliary items, necessary, but repairable by replacing individual parts rather than a complete engine/head/etc, is the likely cause.
A plugged injector, a failed fuel pump, failing fuel pressure regulator, sticky lifter, plugged PCV, open PCV, intake manifold leak, failed EGR valve diaphragm, failed EGR tube, failed injector are a few items that can just quit. I'd borrow the pressure gauge, and a set of NOID lights if available. The NOID lights plug into the injector harness and indicate if the computer is firing the injectors as needed. You may be able to determine if an injector is functional by using a length of tubing held to an ear, the other end held to near the individual injectors, engine running at idle. You should be able to hear the individual injectors 'click' as they open/close the pintle valve.
I had a bad plug wire that caused intermittent misfire. Felt as if a cylinder or two was just not working, I was running on 2-3 cylinders. I went so far as to remove the distributor, the injectors, replaced the TFI, finally checked plug wire resistance. (yours seem good, I had one-two that were intermittent infinite ohms).. oops. Got some used plug wires, plopped them on, bingo.
It might be a good thing to check for intake manifold leaks. Extra air can cause misfire and loss of power.
tom
 

gcaiola

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finally back to this....(where & how to remove fuel hoses from fuel supply manifold)

Since I have a spare car for now I let this slip the past couple of months. But finally back to it. I was convinced the issue was caused by a gasket leak--valve cover and/or lower intake manifold--based on oil residue on part of engine block, as well as other info and input. Now I am up to my elbows ...and maybe stuck.

The valve cover and upper intake manifold are removed. I am trying to remove lower intake manifold, but to do that I must remove the 2 fuel hoses connecting to the "fuel supply manifold" (fuel rail) mounted to top of lower intake manifold. The rubber hoses extends almost to main fuel rail on both fittings, with no special clamp or disconnect securing it--see photo here:
https://photos.app.goo.gl/EEKTxMbLcYLVmfrx5

I tried twisting the hoses just near the ends you see in photo, and I can a bit but don't think I can remove them without damaging the hose as it's old and hardened (so what would keep it secure when i try to re-install later?). I assume the other end of those fuel hoses i's a few feet away somewhere under engine or chassis. Seem unlikely I should disconnect far away from manifold and have a few feet of fuel hose (x 2) dangling off the fuel manifold as I pull it out. That would probably cause more problems/stress/cracking with the old rubber on fuel hoses also.

Any guidance on where to disconnect these fuel hoses and how to do it without destroying them?
 

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First, your fuel rail is connected to your fuel filter st the driver's side inside frame rail. The lines have a quick-disconnect fitting for both lines (high-pressure, and return). To remove the fuel rail, disconnect both lines and remove the two bolts on the intake manifold (2 10mm bolts, IIFR).

For your main problem, sounds like a blown head gasket. Do a compression test and see what the compression in #3 is. If it is extremely low, then a blown head gasket or leaking valves are the most obvious causes - because either the head gasket or valve seats are letting compression pressure leak past them. At the least, removal of the head to look at both the valve seats and the head gasket should be done. And it is not that hard to do.
 

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Thanks for info, zekew68. Sounds like there's no other connection in fuel hose between fuel filter and manifold. That's kinda what I was wondering. I guess that means I need to remove hoses right at connection to manifold.

This sounds silly but I'm hesitant to remove hoses there because I am unsure how to find a suitable replacement for them--since I'm pretty sure they will be trashed afterwards (due to age/brittle/cracking). I am honestly surprised there is no clip/clamp at the manifold side to keep them secured on. Again, refer to link of photo of hoses coming into fuel manifold:
https://photos.app.goo.gl/EEKTxMbLcYLVmfrx5

I'd just plan to replace hoses, but can't figure out if they are custom formed or if I can just buy fuel hose "by-the-foot" to replace them. Doubting that since they must have the quick connect termination on the other (fuel filter) end. Maybe I can buy generic hose with one side terminated? Also have not been able to find the exact replacement PN for the hoses in any ford parts websites/diagrams.

So would appreciate any guidance on that specifically.
 


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