95 Po101

[raymarquise]

95 3800.
A few weeks ago while driving the rpm increased - went into neutral and it shot up to 3000. Shut down and restarted and the rpm went to 1000.
Since then it hunts for idle, and while driving the engine starts to jerk like it's miss firing ( this happens at all speeds). If I come off the throttle the engine will settle down and will run on for a few seconds (like it has excess gas) without me pressing the accelerator.
It finally set a code PO101 - MAF sensor failure.
Changed the MAF but it still runs the same and keeps setting the same code.
Any help will be appreciated.

[LMP]

Very often a failed Throttle Position Sensor gives false readings that contradicts the MAF reading....and the coputer seems to choose the effect as if it were the cause: investigate voltage or resistance reading at TPS as siggested in adjacent post.
ALso, there was a case on this forum where the MAF was not fed with supply voltage for a pink wire that was broken near the large connector on passenger side wheel well.
www.avigex.ca/xport/fuelinject.jpg

[raymarquise]

I should mention the engine seems to run fine in park. It idles fine and I can accelerate through the entire rpm range with no problem. The problems only appear in drive.
Does that rule out the TPS?

[LMP]

I'm inclined to rule out TPS..but the real way to rule it out is not magic or guess: just test for resistance or voltage while depressing throttle, and this will clear or confirm definitely the condition of TPS.
Of course the condition you desribe carries suspicion towards the Idle Air COntrol motor....and failure there commonly brings a MAF alert because metered air is not what is expected.

[raymarquise]

Would a problem IAC cause the engine to stumble while I am driving?
If it will then I have another throttle body with TPS and IAC that I can try.

[LMP]

Indeed I'd be surprised it stumbles while running as main air stream is much larger than anything that would pass through IAC valve whater its condition.....Test the TPS.....0$ and it will make or break this option.

[raymarquise]

The TPS is ok.
Drove with the MAF disconnected - drives beautifully except at idle I have to keep my foot on the gas to prevent stalling. But no stumbles of the engine while driving.