My 2000 grand prix gt is idling really rough and accelerating very poorly and is not shifting gears properly, it stalled a couple of times driving through town. it has new MAF, fuel filter, IAC, spark plugs and wires. Oh and check engine light is on and when you accel over 50kph it starts flashing

SOURCE: 99 Grand Prix GT stalls when MAF is connected

I RAN INTO THIS BEFORE TRY THE IGN MODULE UNDER THE COILS WHEN THEY HEAT UP CARS QUIET AND DO NOT START

SOURCE: 2001 grand am se1. Rough Idle - Spark Plugs and Spark Plug wires

What engine? You need to have it scanned for codes. Autozone will do this for free

Testimonial: "thanks for your quick response!"

SOURCE: own a 1996 Grand AM GT 2.4 quad 4..manual...engine

engine missfire won't start

SOURCE: 1992 pontiac grand am no acceleration, a rough idle (engine miss)

Does it have the 2.3l Quad 4 engine? If so replace the plastic piece that the coils go into, they go bad and leak spark to the cam towers and then you get a nice one or multiple cylinder misfire.

SOURCE: car starts, idles and revs fine when in PARK. Put

You may want to have the catalytic convertor checked out. it may need to be replaced.They can cause a car to run hotter and have poor acceleration to the point that the transmisssion won't shift. Also fuel filter could cause this but not usually. Hope this helps please leave comment.