Mechanics

MAF SENSOR - GT

1999 Pontiac Grand Prix • 6 cylinder FWD Automatic • 178,000 miles

About a month ago, my car would not start. Long story short, the fuel pump was bad. Got it fixed. After It was fixed the CEL was on. At first the code was P0101. Told the person who did the fuel pump was it was and he put a MAF Sensor on. Car instantly ran better. Went to the gas station. When I started the car ago the CEL was off, meaning the computer reset the code. On the way home the car stalled in traffic. Waited a few minutes and it started and got me to a parking lot. Called up my "mechanic" and was told to unplug the maf sensor. Car started without a problem and got me home. I put the old sensor back on which was clearly bad as it was crack clear across the top. So I went out and got a sensor. Car ran better for about 20 minutes then did the same thing the 1st replacement did. Advanced auto swapped out the part for a new one. Also told me the code is now P0102 - low circuit input. I don't want to put this new one on if something else is going to make it go bad again.

Checked the connections to the maf and everything looks okay.(Advanced told me my connection was bad) Never had a problem before the fuel pump went bad. Ugh.

Other little things:
When coasting to a stop on a highway exit, car rpms surge and lights dim sometimes at night.

Sometimes idle is fine, others the rpms surge a little.

What can I do? Don't have much money too throw around. Then again, What broke college kid does? I'm not to familiar with the engine, although I can do small things like brakes and an oil change.
Avatar
Jfkoz0822
December 28, 2010.




The PO101 indicates that the sensor is out of range and PO102 indicates a low voltage issue. Either you have a bad connection, partially broken wire going to the sensor, or the issue goes back to the PCM. What I suggest is to start checking wiring. Check for continunity. While checking it, move the wiring around to see if there is any variation in continunity. Double check the plug to make sure there is no corrosion.

As far as the idle / lights dimming. It sounds like the engine idle is getting to low when you let off the gas. A few things can cause this problem. Cheapest thing to fix would be a vacuum leak, so check to make sure there are none. Also, the idle air control valve (IAC) is responsible to maintain a steady idle. If it is going bad, it can cause the problem too. It is located on the throttle body.

Let me know what you find and I'm here if you have any questions. I remember the college days. Not too much fun.

Joe



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