I have a 96 m6 ss. It has started running rough at low rpm cruising speeds. At idle every once and a while it will start to run rough and drop in rpm and then all the sudden rebound to its normal rpm. The car does not have any emissions equipment, no cats, does have mil eliminators, does have a bigger than stock mass air, and has been programed by PCM4less. The rough running thing seems to be getting worse. I had it scanned and two codes showed up:
P0100 - mass air electrical system
P1657 - skip shift malfunction
I don't believe this has anything to do with the skip shift, but was wondering about the mass air. The car almost feels like the opti is going. Any thoughts?

 

P0100 sets when the PCM sees no change in the MAF sensor reading. Pull the harness connector off the MAF sensor, turn the key on, and check the pink wire for +12V. There have been problems on the 97's with the pink wire breaking somewhere in the harness, a few cases on the 96's. If you've got +12V, and the ground (black/white wire) is good, start the engine. If you have a multi-meter with a frequency function, measure the frequency across the yellow and black/white wires. At idle, you should see about 2,200-2,700 HZ. As engine speed increases, the frequency should rise.

If you don't have a frequency meter, you can use a scanner to look at the MAF sensor reading. At idle it should be in the range of 6 - 8 grams/second (GPS). If the sensor is faulty or the wire is bad, you will usually see an unchanging reading of 461 GPS.

Without a reliable signal from the MAF, the PCM will default to speed-density, and it might be better than with a faulty MAF sensor, but not necessarily perfect.

Its not the skip-shift system that's cuasing the problem. That just means the skip-shift solenoid wire has been disconnected to eliminate the annoying skip-shift feature. You can insert a 2.2Kohm resistor between the pins of the harness connector to eliminate the code, or spend $30 on a "skip-shift eliminator".

 

I only got around 0.1V or less from the pink wire. Thanks for the information, I really appreciate it. Are there any common areas were the wire breaks?