MISFIRING

1997 Pontiac Grand Am

Tiny

webangel

August, 6, 2009 AT 10:21 AM

1997 Pontiac Grand Am 4 cyl 173000 miles

i have replaced the cam sensor, crank sensor, coil, timing chain plugs, tested fuel injectors, changed the plug boots and it still misfires 1 and 3 everything ive done it still misfires 1 and3

FOUND 5709 RELATED QUESTIONS

Engine Miss

52 ANSWERS
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7 Answers

Tiny

JDL

August, 6, 2009 AT 10:52 AM

Hello, a misfire can be caused by just about anything. Did you visually check for spark at the plugs? Fuel pressure ok, use a gage?

Tiny

webangel

August, 6, 2009 AT 12:12 PM

Yesi have visually checked spark have it 1 and 3 still misfieing

Tiny

JDL

August, 6, 2009 AT 12:36 PM

What was the fuel pressure spec? Are the injectors pulsing?

Tiny

webangel

August, 6, 2009 AT 4:09 PM

The fuel pressure was good and the injectors are pulsating could the lobes be worn or valves burnt how do I find out

Tiny

JDL

August, 7, 2009 AT 7:18 AM

You can't check proper fuel pressure without using a gage. Do a compression test on the cylinders.

Tiny

webangel

August, 7, 2009 AT 1:24 PM

Compressioncheck is 180 lbs we did a leakage test and 1 and 3 misfires 2 and 4 has a 25% leakage

Tiny

JDL

August, 9, 2009 AT 10:20 AM

Maybe I misunderstood your post. To do a cylinder leak down test, the engine isn't running. The cylinder your checking, you bring the piston up to tdc compression stroke, pump in air through the spark plug hole, shut the air valve off, watch for a leak-down. Right now, I'm not sure why the misfire.

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