SCAN SHOWED A MISFIRE IN CYLINDER #2.

  • Tiny
  • knicker26
  • 2007 Pontiac G5
  • 123,000 miles

I had the ECM scanned and the code was for a #2 cylinder misfire. I was told it could be the plugs, the injector, or the ignition coil. I suspect its the injector because it idles rough and city MPGs have dropped. Car seems ok on the highway. I'd like to change the injector myself. I need instructions on how to do it.

Wednesday, December 28th, 2011 AT 4:03 AM

13 Answers

  • Tiny
  • saturntech9
  • Expert
  • 28,434 posts

I wouldnt just go replacing the injector without checking things first. Another thing that can cause the missfire is low engine compression and it could smooth out while on the highway. Have you inspected the plugs and wires yet?I would also do a compression test.

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Wednesday, December 28th, 2011 AT 4:33 AM
  • Tiny
  • knicker26
  • Member

I should have mentioned that plugs for all 4 cylinders were changed and the situation did not improve.

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Wednesday, December 28th, 2011 AT 3:19 PM
  • Tiny
  • saturntech9
  • Expert
  • 28,434 posts

Why dont you check the compression of all the cylinders. Auto zone rents the compression to rule that out.

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Wednesday, December 28th, 2011 AT 8:26 PM
  • Tiny
  • knicker26
  • Member

Ok, say I am losing compression in cylinder 2. What are my options? I don't have the funds for a rebuild. The car has 125,000 miles. If I made it to 150,000 I would be happy.

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Friday, January 27th, 2012 AT 2:46 AM
  • Tiny
  • saturntech9
  • Expert
  • 28,434 posts

What are the compression readings?If you have low compression its most likely caused by a valve issue not a ring issue.

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Friday, January 27th, 2012 AT 2:59 AM
  • Tiny
  • knicker26
  • Member

30PSI in cylinder #2. 100+ in 1, 3, 4. Car runs ok on hwy and speeds over 45mph. Idles rough. Idles at 1500RPM. Before it idled at less than 1000.

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Thursday, March 8th, 2012 AT 12:54 AM
  • Tiny
  • saturntech9
  • Expert
  • 28,434 posts

30Psi compression in cylinder number 2 wouldbe what we would call a dead hole. Meaning there isnt enough compression for that cylinder to fire. You said the other cylinders were a 100 plus pounds do know the exact pressures?

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Thursday, March 8th, 2012 AT 1:16 AM
  • Tiny
  • knicker26
  • Member

No I don't I'm afraid. The mechanic told me 1, 3, 4 were at normal level. Someone told me that it was not uncommon for ecotecs to have this problem.

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Thursday, March 8th, 2012 AT 12:51 PM
  • Tiny
  • saturntech9
  • Expert
  • 28,434 posts

I know the early ecotechs had issues with there timing chains tenisors. They are actually a pretty good engine I have see some valve issues here and there cause low compression like yours is doing.

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Thursday, March 8th, 2012 AT 4:41 PM
  • Tiny
  • knicker26
  • Member

I'm still driving the G5. It knocks like that is a valve or cam problem. The car runs rough in the city ok on the hwy. At idle or city driving you can smell gas. On the hwy there is no gas smell. I cannot afford to rebuild the engine, or any other major work. I need this car to run as long as possible. Is there anything I can do to minimize the gas smell?

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Saturday, June 9th, 2012 AT 3:12 AM

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