I've narrowed down my problem to the air temp sensor (I think).

Truck runs crappy...stalls; poor, to no acceleration......rough idle, fluctuates up and down.

It will run ok for a half mile or so, and then it will just die if I give it any gas, sputtering and gasping.

Let it sit with the engine off for a few minutes and it will drive again for another half mile before doing it again.

I thought I might get away with Lloyds fix for his truck, and checked the rotor. Sure enough, it was cracked below the screw.

Replaced the rotor and cap....Still ran like crap, no change at all!

Cleaned and reinstalled IAC...no effect.

Unplug the air sensor = Idle smooths right out! Like nothings wrong. Still drives rough, but not as bad as if the air sensor is plugged in.

Whats up with that? Come on, Answer people!

You need a new one <img border="0" title="" alt="[Big Grin]" src="images/icons/grin.gif" /> . Just kidding.

But seriously. I don't know what may have happened to yours, but if you replace it you'll find everything is okay.

When you unplug the sensor, you are putting the ECU into "safe mode". It assumes that the sensor is bad and bypasses that portion of the circuitry (using a default or generic value in place of what the sensor would normally provide). Most likely the sensor is still "working", however it is giving a seriously bogus value and therefore the ECU tries to adjust the fuel mixture for the wrong temperature/pressure.

Is this what you were looking for?

Well, yes I think. But I'd like to know if this could be the root of the problem, or just a byproduct of some other sensor malfunction. There are just too many things that could go wrong. (not ready to drive it off a cliff, though. <img border="0" title="" alt="[Roll Eyes]" src="images/icons/rolleyes.gif" /> )

Anyway, I have the Raider diagnostic computer tools coming, so I'll figure it out. I'm just sick of dealing with this. I just want to DRIVE it. <img border="0" title="" alt="[Mad]" src="images/icons/mad.gif" />

Well, I got a replacement air flow sensor, and it is not the problem. Its still doing the same crap.

Pretty soon, I'll have replaced every sensor and just about every part under the hood. <img border="0" title="" alt="[Mad]" src="images/icons/mad.gif" />

I'm going to look at the Fuel Pressure Regulator next. But my hopes aren't high. <img border="0" title="" alt="[Roll Eyes]" src="images/icons/rolleyes.gif" />

<small>[ April 17, 2003, 11:59 AM: Message edited by: mrGUY ]</small>

One more problem I've found is a bad seal at the forward end of the CAT. This could definately cause an otherwise happy engine to bog down upon acceleration. And So, although that isn't the first problem, after 14 years, it is probably time to replace that too.

Pull the codes! They're there to keep you from just swpping parts.

I have to get an analog volt meter; mine is digital and I can't use it for that. I was just going to wait for the computer from MarkG, to do that.

Ok, Eddy, I just went down and got another volt meter. No Faults were found. Just a rapid sweap up and down, which means that all is well.

As I expected, after replacing all those sensors anyway. (by the way, all the stuff I replaced with the exception of the rotor and cap, came out of my spare parts boxes)

So I'm back to a shitty running truck and no answers. That cliff is starting to look pretty good at this point.

I'll take it, for god sake dont just roll it off a cliff, I may still need an engine when I am all done with this.

Seriously though... stick with it Guy, you will figure it out. And let me know if I can pull anything of my genI to help you out.

Do you have a spare ECU you could try, even though the one you've got says it's ok?