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

Verify, from several sources, that the part no. for that brand of MAF Sensor is correct. Many replacement MAF Sensors are remanufactured--some are good and some aren't. Try to replace the sensor, if your's came with a lifetime warranty.