Misfire on cylinders one, three and five?

Tiny
SCOT ALAN BRADY
  • MEMBER
  • 2002 SATURN VUE
  • 3.0L
  • V6
  • 2WD
  • AUTOMATIC
  • 170,000 MILES
Started with misfire cylinder 2, 4, 6. Replaced spark plugs (NGK) ignition coil packs (both banks), valve cover gasket, intake manifold gasket, fuel injector on cylinder 6 and all 6 injectors o-rings replaced. 2, 4, 6 no longer misfire. Now I have cylinder 1, 3, 5 misfiring. Disassembly of intake manifold, specifically cover plate and injector cover internally of manifold, was done and reassembled with new sealant. Knock sensor on bank 2 was replaced and no longer have code for p0300, p0301, p0303 and p0305 is present. Compression on all 6 cylinders are within spec. What else could be wrong?
Friday, August 26th, 2022 AT 11:09 AM

3 Replies

Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 109,700 POSTS
Hi,

If I understand correctly, you repaired bank 2-cylinder misfires and they moved to bank 1. How long has it been since the timing belt was replaced? Have you checked fuel pressure?

Are the codes you provided the only one's present? Also, do you have a live data scan tool that we can use? If you do, check the short-term fuel trims so I have an idea of what we are dealing with as far as fuel pressure and check the timing advance signal.

Let me know.

Joe
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Friday, August 26th, 2022 AT 1:43 PM
Tiny
SCOT ALAN BRADY
  • MEMBER
  • 2 POSTS
As far as I know the timing belt has not been replaced. Codes provided are only ones present. I don't have a live data scanner.
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Friday, August 26th, 2022 AT 2:12 PM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 109,700 POSTS
Scot,

If it has the original belt, I have a feeling it is stretched and causing valve timing issues. The idea that all cylinders on one bank or the other misfire, the belt is my first suspect.

I attached the directions below to remove the timing belt cover. I would open it up and inspect it for damage, dry rot, cracks, and tightness.

Let me know if you are comfortable doing this.

Take care,

Joe

See pics below.
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Friday, August 26th, 2022 AT 7:14 PM

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