Pontiac Repair: my car, pontiac grand prix, egr sensor

Question
my car is back firing and want stay running.the rpm's has to stay above 2 or 3  rpm .i have change the spark plugs and wires,fuel filter,and some kinda egr sensor.i have a pontiac grand prix V6 3.1L

Answer
Hi Robert:
What year is this car? when you say it will not stay running do you man it is running rough and you have to keepo the RPM's up to geek it running or does it run okay but stalls? it could be a few things. An egr valve stuck open could cause it to not want to idle. or you could have a couple of cylinder dead "have no spark" and that would cause the rough idle and stalling. That are a lot of different things that could be going on here. And service engine soon light on?