99 2.5L hesitation with missing/stubling

Im a little lost here. The ol ranger developed a miss and hesitation. It's a 5-speed and Under load at low RPM it will trip up a little. Not completely fall on its face but start missing and has noticeably less power. If I stay out of the gas and accelerate moderately thru the gears everything is fine with maybe a miss here or there but power is good and life is great. Although if I try to accelerate fast and get on it, the thing really starts missing and falling on its face. Not to the point where I cant continue to increase speed but a lot of jerking and lurching. Back of the throttle and I can cruise at any speed with no issues. I have ran about a tank of gas thru it since it started and i have not seen any decrease in mileage which I suspected I would.

Not sure if this is related or just a coincidence but this all started suddenly after one morning with a troubled start. I did the whole not turning it over long enough and it didn't start. It was as just about to fire up and I let off the key to early and it die. I have done this before and no problem just try again right? Well when I tried the second time it just cranked for a few seconds with nothing. tried again and same thing. finally, while I was cranking I gave it a little gas and it started to fire on maybe one cylinder, maybe a half a cylinder... I let off the key and it slowly started to pick up the rest of the cylinders but continued to run a little rough. Let it idle a bit but I knew it still wasn't right as in a little miss on idle and then off course all the above symptoms from above.

It just seems odd to me this came on so sudden after the starting episode.

I did the simple stuff.
- Injector cleaner
- New fuel filter (what an absolute PAIN!!!)
- Air filter

any suggestions would help.

truck as 110,000 miles.

OH, and no codes...

Check plugs and wires, look for small vacuum leaks

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I would take a look at the MAF. If it gets a bit of schmutz on the wires, it won't tell the computer you are allowing more air into the engine, and thus the computer won't increase the fuel flow to match. Quick, easy, but be very careful about the wires as they are fragile.
tom

My Ranger did the same thing about a month ago and turned out it needed new spark plugs, wires and a new coil.

10-4 on the plugs and wires.

I will add it to the to-do list for this week...

update to follow.

Ok so I did the plugs and wires last night and I am just blown away...

I now feel as though I am driving the ranger equivalent to a swiss watch. Smooth as silk power with a power band as wide as my mother-in-law. The little guy just purrs...

With this basically being my first rodeo with a ranger I really had no base point when I started driving it back in November. Well apparently it was never quite right. It always ran "good" and felt ok with no complaints but now its just so smooth. I always thought my exhaust by the manifold was a little loud thinking maybe the doughnut was giving out or something but now I believe that was due to some pinging and just plain running a little rough. Now the engine just sounds so much happier and healthier.

It is important to note that I didn't have to much hope that the plugs and wires were going to do any good. I started pulling out the plugs and they all looked great. All were nice and gray/brown with a few that had very minor carbon just on the outer ring by the thread. The wires also appeared good with nice connections and no chafing signs. Also, all the gaps were constant at .045. basically the plugs looked new.

BUT! The plugs were Autolite. I have done the research and from what I can gather there are guys that scream as loud as they can Motorcraft and others say either motorcraft or autolite. A few fall victim to the fancy sales tactics from other brands but who listens to them.

I am not saying that the plugs were for sure the problem and not the wires but there has to be something with sticking to the recommended ford plugs. the truck has 110,000 miles so that means that the autolites were not in the truck for an unreasonable amount of time. They all came out really well too and with basically looking new I really had my doubts.

On a side note, The job went better than expected. I have skinnyish hands and with the right tools it was actually quite easy. I would rather do the plugs and wires ten times in a row over changing another original fuel filter that refuses to come off. There really should be a support group for some of those filter changes.

Thanks guys,

Tom

I had an 88 2.0 with a carburetor and none of the basic plugs did much good. It always seemed a little sluggish (which is pretty much what a 2.0 carb engine is)...then I tried the Bosch +4 plugs and they made such a huge difference that I never used anything else for the next 12 years.

So...yes, they can make a big difference...but there is always going to be loyalty to a favoured brand...like HP and Dell computers...or Ford vs Chevy vs Dodge...

As long as you're happy and things are better all is well...

BTW, I was going to try to find the Bosch +4 for my Fuel injected 2.5 but never got there...not even sure if they make one but they were about 5x the price of the singles electrode plugs...

As I re-read the postings, I thought of an old lima that used to backfire when it started from cold. It had a carburetor that apparently was not adjusted correctly, so barked a bit. It would displace a valve on the PCV whenever it backfired, and the valve being unseated allowed excess air. It would then not idle smoothly at all. I'd move the little valve piece back in place, and all would be well for a while.
Leading to the idea that a vacuum line could have gotten popped off its fitting when you had the backfire. They will not put themself back onto the barbs after being blown away, which would lead to poor idle, and possibly lean fuel:air mix.
tom

Mark, The 88 2.0 had a distributor setup unlike the "newer" 8 plug setup with coil packs. From what I have read from other people's experiences you do not mess with plugs on these things. I have no idea why they are so finicky but I guess they just are. I heard a lot of stories of trying out copper core and multi-electrode plugs and apparently some have horrible experiences and some say they work good for a short period of time but then problems start to creep in. I paid $5 a plug for the Motorcraft plugs which isnt really that cheap but I can tell you that they made a huge difference. I mean YUGE!

I think in this case its not necessarily brand loyalty but just leaving well enough alone. Cross my fingers that I continue to see good performance for many miles to come.

Good to know you found that solution fast enough to save you some money.

I was trying so many things to make it better and these things may not be expensive on their own but when you try different things many times that all cost a bit it turns out to be a big $$$$ drain.

It's good that so many people have good experiences and can share them but that's where the brand loyalty becomes a disadvantage. I try not to promote anything in particular because there is always someone who will say Brand X is better than Brand Y.

I didn't get to try the +4 plugs because I ended up selling the Ranger before I really got to drive it with the 2.5 fuel injection. They can be surprisingly powerful little engines when they work right and everything is in top shape...

Have you checked the cable for play in the pedal by any chance? This one simple mod can make an even bigger difference and doing that on my 2.0 restored my faith in small engines...

Check it out if you haven't already done so...might give you that little bit more that should be there...

http://www.therangerstation.com/Magazine/Summer06/throttlecablemod.shtml

Ok so I have to revive this thread because once again I developed a hesitation and missing.

This time around it only seems to be when I am on a rough road and accelerating? It may happen when I am not in the throttle and just cruising but its hard to tell as hearing/feeling the miss is hard. I only really notice it when I am in town.

-I checked all the plug wires that I just replaced thinking one was loose and the vibration was causing it but that didnt help any.

-I replaced the ground to body as it was showing a little corrosion. the ground to the motor is good.

With my little experience with these rangers not sure if this is something that anyone has seen or dealt with? Haven't been able to dig anything up from past threads.

Could it be a failing coil pack?

its really annoying.


Tom

If it only happens on rough roads it could be a wire grounding out or a wire harness that is worn or burned through that is touching metal. I've seen that on my own vehicle and have read where others fixed a hesitation problem by wrapping a damaged wire.

Could be a coil pack issue but it would probably be caused by a wire issue in that case. The coil packs may be damaged somehow internally but they are not something you can diagnose. Swap the coil packs around and drive it like that for a while. If the hesitation disappears when you swap the coil packs then you can pretty much confirm it was the main coil pack (exhaust side fires first on 8 plug engines).

Since it seems to be intermittent it and (seemingly) related to bumpy roads it could also be fuel pressure issues...particularly inertia switch. The inertia switch is up under the dash and in some cases a bump can cause the switch to shut down the fuel pump. I had one on my 89 Tempo that would cause hesitation and the odd stall but was not diagnosed until after I swapped the fuel pump and numerous other parts (including the engine and transmission) only to have the car die on me on the way home from the service center.

NOTE: A quick test is to simply bypass the inertia switch and drive for a few days to see if it clears up...but...this is a safety switch to shut down the pump in accidents so be careful...you don't want to disable that for any longer than needed to test.