1999 Pontiac Grand Am 1999 Grand Am Misfiring

123,000 MILES • 4 CYL • FWD • AUTOMATIC
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TWISTEDSAINT999
  • MEMBER
  • 1 POST
I have a 2.4L quad-4 engine that has a misfire in one of the cylinders and carbon buildup in the throttle body. I ran a can of Seafoam through the intake and one through the oil to clean everything out. I checked the compression and it has 125lbs after 5 cranks and all cylinders are static. I replaced the ICM, both coil packs and the spark plugs. The only thing I can think of now is the EGR valve but I don't want to spend $100 if I don't have too. What is wrong with my car?
Nov 13, 2009 at 10:10 AM
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MMPRINCE4000
  • ✓Experienced Mechanic
  • 8,548 POSTS
Use a noid light to check the injectors are firing.

The EGR would (generally) not cause a single misfire, EGR flow at idle or low speed would cause stumbling and multiple misfires.
Nov 14, 2009 at 1:04 AM
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