[Abs_1986]

I have a 2002 Grand Prix GTP supercharged 3.8L

I was having a problem with my car stalling when I put it into drive or reverse as it would bog down. The diagnostics indicated it was the mass air flow sensor. I changed the mass air flow sensor and the problem persists. I have unplugged the mass air mass flow sensor and this has made it so my car does not stall, but it has caused my car to idle between 2000-3000 RPM and it does not have the same zip the it had before.

Any help would be appreciated

We don't want to take it to the garage and tell us again that it's the mass air flow sensor that needs to be replaced and have them know it's another under laying issue and gauge us!

[TxGreaseMonkey]

I would replace the Ignition Control Module (ICM), especially if you have over 120,000 miles on the car. It's very possible this is the cause and it's easy to replace yourself. Be sure to disconnect the negative battery cable, before beginning any work.

[Abs_1986]

What would the icm do?

[TxGreaseMonkey]

Conceptually, the ICM is a large output transistor (switch) controlling current through the primary coil. ICMs replace points and condenser in older vehicles. In the primary coil, current builds to 5 to 12 amps, generating lots of heat (due to inductance). Then, the ECM controls when the ICM "switches off" current to the primary coil, causing amperage to go to zero. When this happens, 12 to 14 volts in the primary coil is "stepped-up" to 30,000 volts in the secondary coil. This process creates a type of alternating current required for the coil (step-up transformer) to work. In a properly working ICM, timing is precisely when needed to fire each spark plug. In other words, it controls dwell or on time of the ignition coils primary winding. When not replaced, the vehicle could experience no or hard start, long crank time, misfire, stalling, lack of power, erratic or incorrect rpm, inconsistent transmission shift points, spark plug fouling, catalytic converter failure, poor fuel economy or CEL/MIL illumination.

ICMs are the most problematic component on engines that have them. Eventually, heat takes its toll on them and they start adversely affecting engine performance. It's not uncommon for the incomplete combustion to allow gas to build-up in the exhaust system, which is later ignited. It can result in the exhaust system being blown off the car.

[Abs_1986]

My father and also a GM dealership have connected a scanner and the code reads it's the mass air flow sensor, although has been switched and continues to do so. So what would that be if the code reads it's the MAF? We are going to attempt to clean and it check the voltage of the wires before proceeding to do anything else! Would you recommend this as well?

[TxGreaseMonkey]

Yes, be sure to clean the MAF Sensor connector before doing anything else. Be sure the seals around the MAF Sensor are in great shape and not leaking. I doubt trying to read the voltages will work.

[TxGreaseMonkey]

How many miles are on the car?

[Abs_1986]

130km