I have a 93 22RE pickup. This truck has been running strangely. First I had a code 41 (intermittent). I removed the throttle body, cleaned and tested (100% test through entire rotation of TPS) and bench set it. Problem returned and I did it all again.

On a just to be sure basis I removed the intake and cleaned the MAF sensor as well.

Now when the truck is warm I get an intermittent CEL. The truck will run rough and stutter. I can smell that it is lean as well. Then the light might go out and it runs fine...then it returns again. I have tried to jumper to get the CEL codes but the codes are gone when I look.

 

If your not able to get the codes you might just not be either putting the jumper in all the way or jumping the wrong terminals. Also make sure you are setting the tps to the exact measurement. Make sure coolant is burped and has no bubbles in it

 

jump the T and E1 ports of the diagnostic port to get codes.

 

If problem seems temperature dependent, eliminate doubts on temp senders AND THEIR MOUNTING THREADS. Those need to be cleaned at least once every 24 years.
Simple and free procedure.

 

Intermittent Check Engine Light that leaves no code in the computer from my experience has been due to vacuum leaks. How are the conditions of the vacuum lines? Are they routed correctly?

I cant recall right off what code 41 so you will need to that problem worked out. As far at the TPS, they have been cycled millions of times. I do not change many sensors but the TPS and O2 sensors are the ones I will replace with the factory replacement part. Most others can be cleaned. There is a thread on here about cleaning the contacts on the TPS and it can help but I have seen the original TPS pass test and still have issues. I just replace the TPS if I suspect any issues with it.

In most cases the erratic idle is from air in the cooling system. You need to raise the front end as high as you can and with the radiator cap off let the thermostat cycle 3-4 times. On here it is known as Burping the System. I am six foot tall and when I have my front end up, the Core Support is at about my shoulders height. It needs to be raised fairly high.

have not tried it but supposedly there is a way of squeezing the radiator hoses that can force the air out. I have not tried that way.

 

All vacuum lines are relatively new. I have cleaned all grounds and tested continuity. I have checked everythingI can. I am beginning to believe it is an igniter and or ECM issue. Working on it.

With regard to burping. I fill it all the way up then I use a laser thermometer to check the temps of hoses and parts surrounding. It proves that there is no air gap.