1997 PONTIAC GRAND AM MISFIRING

  • Tiny
  • webangel
  • 1997 Pontiac Grand 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

Do you
have the same problem?
Yes
No
Thursday, August 6th, 2009 AT 10:21 AM

7 Replies

  • Tiny
  • JDL
  • Expert
  • 16,289 posts

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?

Was this
answer
helpful?
Yes
No
Thursday, August 6th, 2009 AT 10:52 AM
  • Tiny
  • webangel
  • Member

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

Was this
answer
helpful?
Yes
No
Thursday, August 6th, 2009 AT 12:12 PM
  • Tiny
  • JDL
  • Expert
  • 16,289 posts

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

Was this
answer
helpful?
Yes
No
Thursday, August 6th, 2009 AT 12:36 PM
  • Tiny
  • webangel
  • Member

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

Was this
answer
helpful?
Yes
No
Thursday, August 6th, 2009 AT 4:09 PM
  • Tiny
  • JDL
  • Expert
  • 16,289 posts

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

Was this
answer
helpful?
Yes
No
Friday, August 7th, 2009 AT 7:18 AM
  • Tiny
  • webangel
  • Member

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

Was this
answer
helpful?
Yes
No
Friday, August 7th, 2009 AT 1:24 PM
  • Tiny
  • JDL
  • Expert
  • 16,289 posts

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.

Was this
answer
helpful?
Yes
No
Sunday, August 9th, 2009 AT 10:20 AM

Please login or register to post a reply.

Similar Questions