A friend of mine recently purchased a 98 Grand Prix GTP that was throwing MAF sensor codes and, after a bit of driving, transmission solenoid codes. He was told by a mechanic that his 3.8 non-supercharged was throwing similar codes and he resolved the issue by replacing a bad MAF sensor. My friend is also having problems related to shifting into 3rd and 4th gear at higher RPMs, which the mechanic mentioned could also be from a bad sensor. After popping out the old sensor and replacing it with a brand new one, the car fails to idle and dies. The engine will run if given some gas, but if he tries to drive it at all it stalls.
Tomorrow my friend and I plan on looking for any vacuum leaks or other problems related to airflow, but if anyone has any ideas on why the car would fail to idle or start from a brand new sensor, I'd appreciate any help I could get.