Pontiac Grand Prix 2002 runs rough

While you're driving down the road normally, does the vehicle perform properly? This could be an example of an air / fuel mixture concern, which will required some troubleshooting, hands on, measuring data with a diagnostic trouble tool. Physical inspections you can do - ensure your air box is sealed and closed properly, and that the air tube is without leaks.

Check your air filter, make sure it is clean. Check your air duct work to your air box. Make sure it is connected. Is there a check engine light on? Borrow a scan tool from an auto parts store and run it to get the codes. You could have a bad mass air flow sensor or your crank position sensor may have failed. Either way there should be a check engine light on the dash and that is how you find out what the cause of the issue.