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P0102 code, stuttering stalling 3.8L grand prix gt

R

randybill

New member
the car- 2000 Pontiac Grand Prix GT 3.8L naturally aspirated. Stock, no mods right down to paper filter.

the problem- check engine light on. idle not steady at all times, Stalling when driving and hard to restart. Only code that comes up is P0102. replaced maf, map, and iac due to miles on car 151,XXX and i was hoping for an easy fix.

after i replaced those three parts, the code was cleared and the car was perfect for 130 miles. now i'm having the same problem again with the same code.

the measurements- the keyed voltage to the maf is 12.01 VDC and the PCM wire at the maf is 5.0VDC. both voltage readings were ground referenced to the middle ground wire going to the maf.

i've also check the battery voltage at the battery terminals and got 12.74VDC then put the ground lead from my meter on the engine and the meter read the same 12.74VDC. so i'm pretty sure the engine has a solid ground. although i haven't ohm'd out the ground.

the p0102 code is a low voltage reference to the maf so that's why i'm hitting on the voltage stuff. am i going in the right direction?

next i'm going to unplug the o2 sensor to see if that is causing the problem.

what else should i try? this is a very confusing issue. it also seems it is a somewhat common problem with our cars. ideas??? :confused:
 


i have not checked for vacuum leaks but based on the way the car acts, runs perfectly then has it's stalling episodes. leads me to think electrical since the problem is somewhat intermittent.

is there such a thing as an intermittent vacuum leak? i'm not against searching for vacuum leaks. i had ruled that out just because of the way the car acts.

example- after i replaced the maf sensor i had 130 miles of no codes and no problems.

is there a certain place i should look for vac leaks that's problematic on these cars? i've read on the supercharged cars there is a "y" connector that often leaks. is there something similar on the n/a cars like mine?
 
had a chance to check the frequency tonight and the new maf ref wire is 2.5VDC but only 104Hz at idle. (should be from 1200Hz to 2000Hz at idle) even by revving the engine a bit from idle the freq jumped to about 400Hz. i guess it's possible the "new" maf is bad too?



that would explain why i had 130 trouble free miles with no symptoms and no p0102 rearing it's ugly head. i'm going to the store to exchange the maf tomorrow.
 
i haven't had a chance to exchange the maf yet so this is what i have done so far:

i ohmed out the the ref wire from the maf sensor to the computer pin #69 and the wire appeared to be good with little resistance. reassembled and tried to restart. wouldn't restart. after several attempts, i unplugged maf connecter and car started. drove to work today. hopefully no tow bill for me today...

i have a friend that has scanning software on his laptop. i think the car is ok to drive to his house. i'm going to have him scan the car before i spend anymore money on this thing!

if the car runs well for me today i think i can eliminate a vacuum leak for sure. :)
 


after ohming out the maf wiring and looking for shorts, checking fuses and looking for good grounds. it turned out to be 2 bad maf sensors in a row. i bought a junkyard piece and now the car has ran great for a week!
 
I am having the same problem. I was getting the p0102 code. So I replaced the MAF with a new one. I am no longer getting the code but the car is still stalling. And now it will not start without giving it gas.

Any ideas where to go from here?

Thanks,
Ed
 
unplug the maf and try to start the car. if the car starts up and drives better then look into your maf sensor and/or maf wiring and voltages/frequencies.

that's what i did as part of my troubleshooting my "new" maf sensor. eventually all fingers pointed to a bad maf and once i replaced the maf a second time. viola! the car ran fine.
 


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