Mechanics

MISFIRES ON 3 CYLINDERS

2000 Pontiac Grand Am

Engine Mechanical problem
2000 Pontiac Grand Am 6 cyl Two Wheel Drive Automatic 172000 miles

I have a 2000 Pontiac Grand Am Se with 172,000 miles. It has a misfire on 3 cylinders. At idle it runs rough and low. As I accelerate more it seems to be much smoother. Also I get horrible gas mileage when it's supposed to get 20-32 mpg. I've replaced the plugs, wires, coils, and the ignition module. It also shows no signs of a leaking or blown head gasket. Could it be the fuel injectors or computer?
Avatar
Treflip98
July 6, 2009.




Have PCM scanned at most autoparts stores for free.

Report any codes. Other sensors that are out of range will cause a rich mixture and misfires, coolant sensor for example.

You also could have a clogged CAT.

Mmprince4000
Jul 6, 2009.


AD