misfires

2004 PONTIAC BONNEVILLE
100,000 MILES • 3.8L • 6 CYL • FWD • AUTOMATIC
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NOTAPROMIKE
  • MEMBER
  • 66 POSTS
My 2002 Bonneville was running fine when I noticed it was not running smoothe. I could feel it misfiring and has little power. This came on all of a sudden and very noticeible. When idling if you put it in drive with the brake on, the engine shakes. O'Riley's Auto pulled a few codes out but the one that I suspect and need more info on was the message "multiple misfires". Where do I start? What do I look for? In what order? Plugs, wires, sensors, etc.? There was also a code for the powertrain Control Module which I know nothing about or it's location. Thanks for any information to all who help. FYI my last problem was fixed with a new crankshaft position sensor. I replaced that after reprograming the keys with the computer failed to fix the problem. The car (04 Bonneville) has not failed to start since then. Mike
Mar 16, 2016 at 8:06 AM
Repair Safety Notice: This information is for general instructional purposes only. Vehicle repair can be dangerous. Verify all information, follow manufacturer service procedures, use proper tools and safety equipment, and consult a qualified repair shop when needed.
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MIKE H R
  • AUTOMOTIVE REPAIR CONTRIBUTOR
  • 3,094 POSTS
For the heck of it disconnect the battery, leave off for a couple of minutes, with it disconnected cross the positive cable to the ground. this will clear the ecm. After a couple minutes reconnect it and see if it starts.
Mar 16, 2016 at 8:31 AM
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