Originally Posted by
IARLLC
Code is probably a P0101. MAF not reading what the calibration thinks it should. If that MAF is intalled in the 4" intake tube, the speed of the air is much lower than it was going through the smaller stock intake tube. This will cause VERY LOW expectations from the PCM. It just thinks that you are breathing less so it commands less fuel, lower trans pressures, wrong timing, etc. No big deal. If that is the case, you need to tune the MAF.
I'd still go through and tune the rest of the system. Just saying that tuning the MAF will seriously improve your situation.