had replaced all coils,ignition mudule,and plugs and still have mutiple misfire. on 1999 Pontiac Grand Am

replaced parts and still the same no power and rough idle

by in Orlando, FL on August 02, 2012
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2 answers
ANSWER by , August 04, 2012
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.
ANSWER by , August 02, 2012
Sounds fuel or compression related. Have you checked compression or performed an injector drop test?