I just scanned my car to find the following codes, 100 and 1657. The 100 code is-Mass Air Flow (MAF) insufficient signal activity, and the 1657 code is-Skip shift/One to four upshift system control circuit, which is probably why it need to push my shifter into reverse. Anyways, this must be a short somewhere, or a bad wire. Since both of these are not functioning, instead of just the MAF for example. Anyone know of a good way to track down a bad ground, or a short? I'd really like to get this fixed, because 15mpg isn't all that fun. Any ideas of help would be great.

 

You have checked the presence of 12 volts on the pink wire to both the MAF and Skip shift solenoid right? Both are powered by the 20AMP #10 fuse in the underhood fuse panel. But then so are the O2s and you didn't mention a problem with them.