MAF sensor replaced at dealer and the idle still fluctuates along with the car bucking when going into reverse and drive.


Asked by Dec 15, 2013 at 07:35 AM about the 2004 Pontiac Grand Am SE1

Question type: Maintenance & Repair

The other day my car began idling erratically, jumping between 1000 and 2000 rpm
while idling, the check engine light came on and then the car shut off. My car started up
after a few moments and I was able to get home but the rpm at an idle still jumped up
and down.
Next morning I took my car to the Chevy dealership. The idle no longer jumped up and
down but now idled around 1700 rpms upon start up.
I was told that I needed a new MAF sensor and told them to go ahead and change it. I
picked up my car just before they closed. It seemed fine for about a block and then the
idle began fluctuating again along with the car lurching when being put into drive and
I tried disconnecting the battery for ~15 miin and starting the car with the parking break
on. Let her set and then the idle dropped down to 1000 rpm where it stayed. When to
test drive around the block and immediately experienced the lurching when shifting into
drive and reverse, then the idle actually dropped below 1000 rpm. When I tried to rev
the engine the rpm's would kick back as soon as they got up to 3500 rpm.

I feel like the dealer misdiagnosed my vehicle and I paid for a part that was probably
working properly. Any ideas on what could be causing my car to behave this way? Did I
just pay $500 for a part that I did not need?

4 Answers


Possibly, without knowing the code we would only be guessing. I'd look into a vacuum leak or the idle control value or throttle body being dirty as some examples. But take it back and have them make good and get it working correctly.

1 of 1 people found this helpful.

The code was DTC P0102. I got the code from the repair invoice. I have been reading that it common to mistake that code for an MAF sensor when it is really a vacuum leak. Will be taking car back. I just want to have a leg to stand on when I get there. Kicking myself for not requesting the old part now.

119,825 -- check the wire harness for the maf. They might not have it completely plugged in? Did your check engine light come back on? I agree with Tom sounds like it could be an idle air control valve issue or a vacuum leak. Check pcv valve. Make sure it is operating properly and not stuck open or hose is leaking vacuum.

1 of 1 people found this helpful.

Yes the check engine light came back on. Thank you guys. Taking my car to another shop and will have them check for those things. Sure would be nice if it was just that the maf wasn't completely plugged in!

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