1999 Pontiac Grand Am Q&A
1999 Pontiac Grand Am Question: had replaced all coils,ignition mudule,and plugs and still have mutiple misfire.
Sounds fuel or compression related. Have you checked compression or performed an injector drop test? - Chevy Power
Any other codes besides misfires ? Any ability to read live data? Access to a vacuum guage--easy check for valve related problems often overlooked is with an old-fashioned mechanical vacuum gauge. - ziptie12