Craptastic stall at highway speed

[JibbaJibba56]

I the bumpy lumpy rough idle and my truck will stall when I am cruising on the highway. I can shove my foot on the gas all the way when I catch the rpms dropping to zero and this still doesn't recover my truck. I had the engine scanned recently and it took me to a bank one problem of 4 things, spark plugs, wires, O2 sensor, injectors. I replaced the plugs and wires, didn't really want to dig into the injectors (I have been using cleaner on them) but I did notice that my O2 sensor has basically been messed with before (I recently acquired the truck). The nut was stripped to nothing and the housing was damaged to say the least. Could an O2 sensor make it that bad? I had it replaced this morning and the stall at highway doesn't occur but idle is still garbage. It will stall when i take it out of gear to coast to a stop or during moderate braking.
Also, when I did the plugs and wires everything worked the same as before I did them and trust me these things needed replaced as some of the plugs no longer had tips on them and the wires would crumble in your hand.

Please help me out.

 

[KELLY88]

If you've got bad idle then go to the basics. You already did the plugs and wires, are you absolutely sure the firing order is correct? Also check the air filter, fuel filter and idle air control.

 

[JibbaJibba56]

check fire order 5 or 6 times and did them one at a time to be sure of that. it seems to be limited to slowing down or stopping, possibly vaccuum as I did remove the upper intake to pull those plugs and inspect the hoses attached to the underside of the intake manifold. I say this as it seems to be during anytime i summon the brakes. because now when i initially start it runs as smooth as ever.

Also, where can I find how to do this IAC business that everyone speaks of and how hard is it to clean it up and what not?

Thanks for the help.

 

[KELLY88]

IAC is real easy. It's right behind the throttle body on the upper intake. Easy way to test it is while the truck sits at idle you unplug the IAC. If the engine bogs down then your IAC IS working. If the idle doesn't change then it's NOT working. If it's not working then take it off and spray it down with either carb cleaner or throttle body cleaner and reinstall. You also said you took your manifold off to do the plugs. Check again that each bolt is secure and check over your vacuum lines again. If there's nothing obvious then shoot your vacuum lines and the seal around the manifold with carb cleaner. If your engine bogs down at some point then you have a leak where you shot at.

 

[JibbaJibba56]

nice. It's good to have people that know their stuff. You guys should see this O2 sensor they pulled out, it is fierce. As far as that vacuum trick of shooting cleaner at hoses. Why would that make it change idle? or am I missing what you're saying here? I have made and repaired gas tanks and have done pressure checking with soap to see bubbles to locate leaks, would that work for this application?

Again thanks, I love my ranger and this forum. When I get my heap working great again i'll post some picks of my custom fab deer getter bumper.

 

[KELLY88]

I don't know a ton about these but I spent about a month on and off trying to find an intermittent idle problem and went through all this before. The way the carb cleaner trick works is that since the engine makes a vacuum it's sucking in rather than pushing out like a gas tank. So if you shoot cleaner where there is a leak, that cleaner will get sucked into the motor and ultimately into the cylinders causing a change in idle depending on which fluid you use (shooting with starter fluid would make a higher idle). Pressure testing like what you mentioned has higher than normal atmospheric pressure so it blows out through the leaks. Engine vacuum is lower than normal atmospheric pressure so it sucks in through the leaks.

 

[JibbaJibba56]

So I have done the vacuum line test. All pass. Great test by the way as when you miss you end up cleaning things up a bit in the engine bay. I did unplug the IAC and the engine dogged a little bit, but not much. But when I plugged it back in the engine ramps up rapidly and I can hear that thing working back and forth for a few seconds and then the engine idles way way down then up again to the original bad idle. To me it seems like it sticks just not all the time. The truck has been running really great lately but on a few occasions chokes when dropping to idle. It never stays choked at idle once i recover it using the throttle, once i rev to around 2000 for a brief moment it will idle rough but enough not to stall, say 500-600 rpm. Ideally I would like that to be the low idle when using things like the breaks hard or turning the steering on dry pavement, things to that affect that really load an engine.

I removed the IAC and sprayed with Cleaner and am currently soaking in lucas oil injector cleaner. good idea or bad idea? it is set up to run fluid downhill away from the electrics if that helps.

 

[Joelzme]

Did you check your MAF? I had the a similar problem and did most of what you said, bu it ened up being a MAF that was dead and it never threw a CEL. You could try cleaning it.

 

[JibbaJibba56]

I put the IAC back on last night and this truck is running like brand new. Idles superb, better than when I bought it for sure. There is a CEL still on but I assume it would need cleared they just don't go away, right? If the truck is running sweet should I still check out the MAF for cleaning?

 

[Joelzme]

Sounds good.

Usually when the problem is repaired the CEL goes off. In your case I would still pull the code to see what it is saying. You might have cleared up *part* of the problem, not the whole thing. You can go to Autozone and they will do it for free and give you a printout.

Cleaning the MAF is up to you, just follow the directions on the bottle or online here so you do it right and don't damage the component. They are expensive to replace....

Joel

 

[KELLY88]

Good to hear that the engine is running better. As far as the CEL code, it might go off after a while but it still wouldn't hurt to get the code read. Also agreed that it's a good idea to clean the MAF, can never hurt to clean something so long as you do it right. Make sure you do the reading, the MAF sensor is real sensitive and easy to mess up.

 

[JibbaJibba56]

How long can you run a purposely plugged EGR Valve. I found mine was sticking so I plugged the hose. It runs really nice this way. Is there a mileage affect by doing this? Are these cleanable or is this an electronic sensor type? I am not too worried about emission test.

 

[Dusty_Ranger]

check the fuel pump relay connections to the battery that was happening to mine and it turned out to be a loose relay power wire to the battery

 

[JibbaJibba56]

all 'fixes' seem to be temporary. what is wrong with this piece of garbage. although it is not stalling as much as it used to it is still stalling at least once a day. Some more details of things I notice. When I get out of this truck it smells so rich it makes me want to vomit. I am pretty sure that when I am riding with the window down the fumes are getting into the cabin. These fumes are thick and make me feel very dizzy. I do know that the driver side is the only side that smells like this. If I walk around the front of the truck and smell the passenger side it smells so faint of exhaust and not at all of fuel. The driver side though is so potent you notice it as soon as you open the window or the door. What is this all about?
I need this truck to drive 900 miles home friday from minnesota. If it makes it that far I am dumping this piece of garbage asap.

 

[Sevensecondsuv]

Fuel Pressure Regulator gone bad? It could be letting the engine run at 100 PSI fuel pressure which would explain the pig rich condition. Get (or rent from autozone) a fuel pressure tester and see what the pressure at the fuel rail is. There is a little valve on the fuel rail that looks like a tire valve stem. Connect the pressure tester to this and turn the ignition on (don't start it). The pressure should be about 33 PSI.

Running pig rich would also explain how it keeps fowling O2's and spark plugs.