Failed sensors don't always throw a code. Thing is, if the sensor is way out of spec, you'll get a code. But otherwise, the PCM often can't differentiate between a failed sensor and the "thing" that it's sensing simply not doing anything. Hard to explain, but a good example (not related to your issue) is the CPS. A CPS with resistance that's way off will throw a code. But one that simply isn't responding to the reluctor on the cam gear won't, because the PCM will just "think" that the engine isn't turning.

I could imagine the same thing happening with the IVS. The PCM doesn't know the difference between the IVS circuit opening and the driver briefly getting off the pedal. So between the two, I would suspect the IVS more than the TPS.

 

I'm not sure a DVOM could capture a power flicker.

 

Yea Phil, that thought has gone through my mind over and over. Don't have a scope so that is the best I can do. Couple of weeks ago I was inserting small pieces of wire in the back of the TPS and IVS plugs to measure voltage and the truck ran for a week. My thinking was, I shuck something up. I'll let y'all know if the pedal assembly helps.

 

THe IVS can be read with a meter (On or off) . The TPS can be as well .

 

"The observer effect" in action.....

 

Easy now madpogue! We don't need to get started on quantum mechanics and schrodinger's cat.

 

I have metered both and got correct readings, just hoping it is intermittent.

 

Hey Phil, I'd take a quantum fix. At least I would think it is supposed to work!😜

 

What where the readings ?

 

Rick, I got 12volts and 0 volts from IVS and .63 to 3.8 volts from TPS. I know things can test good and still have bad spots in them. That is why I am going to try another pedal assembly. There is not much left to change out except the whole truck!

 

No luck so far. I changed the TPS and the IVS(which is replaceable) and still have problem. I idled truck at 1500 rpm for 30 min and no faults. Started varying throttle and wham, it failed. I was wondering if the IDM could be causing this problem and not throw a code? Any suggestions? Thanks, Charlie

 

Are you still getting the WTS light when it drops to idle? If so, it's still pointing at PCM power interruption.

 

^^^what he said

 

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Yes Madpouge, still getting the wts when it fails. My thinking was the idm is on the power feed going to the pcm and I was thinking it might be interrupting the power to the pcm. Got a loaner idm and I'm going to see what happens. Oh yea, will a idm for a 97 work in a 96?