I have a 1998 Grand Prix GTP. It is doing this thing where it will start jerking and when it is doing this there is some kind of bad rattling, something in the motor just sounds like its going to fall off. What could that be? Also, aside from problem one,

my check engine light has been on for some time and a code reader indicated mass air flow sensor which I replaced (twice) and it ended up coming back on again and is showing the same code which also says it could be the MAP sensor. What are the symptoms of a MAP sensor going bad?

It happens worse when at an idle such as stopped at a stop light but it does occur while driving at a steady speed and throttle which then is like a sputtering almost like it is not getting enough fuel which also I forgot to mention, when it is doing it it seems to suck my gas down bad. I also forgot to mention that I just had the spark plugs and wires replaced too.

Answer: For the fuel being used quickly, a common problem is the fuel pressure regulator leaking internally into the vacuum line, causing a rich condition.This could be the cause of the poor running, and cause the belt to be jumping and giving the rattle. Or the noise and running problem may not be related at all, hard to say. As for code, a MAP sensor can also give a MAF code. But they way it is running may be the cause of the codes coming up, or the codes are the reason for it running that way. This is a condition of a bad map sensor or MAF. The map sensor is fairly inexpensive and I would suggest replacing it since it does not seem to have helped. Check the wiring terminal at the MAF carefully, have had some of those wires break right at the connector.


IAT Sensor Wire Colors

2006 Pontiac Grand Prix 3800 series
Engine Size : V6 base engine
Question : what are the colors of the 2 wires connected to the IAT sensor (I have 5 wires) i was told only 2 wires connect to the sensor please email me the the color of the 2 wires ..thanks.

Answer: Yes, there are 5 wires because the Intake Air Temperature Sensor is an integral part of the Mass Airflow Sensor (MAF). The two wires that control that function are tan and black, but if you're having issues with it, you should probably replace the entire Mass Airflow Sensor. If wires are broken, they can be repaired easy enough. Just be sure to use correct wiring connection techniques so you don't have future trouble.


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    • Guest - Calvin williams

      1998grand prix supercharged crankshaft but won't start

    • Guest - ada,

      I have the same problem with my 1998 GTP. My GTP has a light jerk when it idles but my engine light just came on, but it's been doing it since I bought it about 3 weeks ago and I have the same rattleing noise. If yours is a GTP, the noise is the coupler in the supercharger. it's an easy fix. Total cost is about 50 dollars for the coupler and the supercharger oil.

    • Guest - Tech

      In reply to: Guest - ada,

      Thanks for the information Ada.

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