MIL ON : Code P0101

2002 Chevy Blazer 4.3 Vin W engine, Automatic, 4X4, 91,000 miles
Has this as an intermittent problem. 99% of the time it happens while going uphill under load.
Code lists out as MAF : Circuit range performance problem. The MAP value is always the same in the freeze data. It does change when viewing live data though. It never shows a negative pressure in the intake though even when going downhill with a closed throttle where I would think the engine would draw a vac in the intake, so I am thinking that it is possibly the real problem.
Typical freeze data read with an Actron CP9145 scanner.
TPS : 70 - 73.7 % - RPM : 3000 - 3480 load : 50 - 59% MAF : 11 - 12.9 MAP : 26.9 "Hg Speed : 40 - 46 Mph
MIL light shuts off after 3 restarts and it may go 2 weeks without it coming on again.
It has had a new set of plugs, wires and the intake gaskets were changed out with no effect on the code (done more as a preventative anyway since I had some time to work on it and this problem doesn't seem to effect the drivability). Cleaned the MAF and swapped it with a different one, same readings with the new unit so I swapped them back.
Figure I'd ask for other opinions.
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Steve W.



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check the map readings key on engine off, then check it running at idle see what you have, the running readings are the difference between the atmospheric press. and the engine vacuum. It is possible the pcm is being fooled by what it percieves to be expected air flow from the maf based on engine load calculated from the tps and map. Going up hill under load should not be 26.9, that is atmospheric pressure, something is awry. Not completely familiar with this engine ,does it have a map?

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Shep, MAP is in the intake on the pass side. KOEO it shows 26.9. Idle shows it at 13.4 - 12.2. It seems to track OK with throttle position though. TPS is clean with no opens through it's range. Just want to be a PIA. I was hoping that it was a bad harness connector or bad vac. line. Checked them over and nothing wrong there.
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Steve W.
Near Cooperstown N.Y.
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map/baro seems lo, what is your altitude? I am in the LK George are.

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That is why I'm thinking the MAP is the problem. I think I have one that will fit off another vehicle so I'll just swap it and look at those readings. I was up in your area for Americade.
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Steve W.

"Shep" < snipped-for-privacy@capital.net> wrote in message
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My daughter works for Americade, handled all the registrations.

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Well finally had a chance to work on the beast. Tossed a new MAP in and checked the readings. Had 29.2 KOEO with a new one. Idle showed 11.4. Ran it through the gauntlet and no light. Will see if is stays off.
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Steve W.


"Shep" < snipped-for-privacy@capital.net> wrote in message
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