Cylinder 3 continues to missfire. Replaced all plugs, wires, coils and icm.

  • 85,000 MILES
Hi Everyone, I have tried to search for the answer but can't find it.

2003 Venture 3.4L V6 - 140000 KM on it.

History of problem:
Saturday afternoon I merged on to the highway and after a couple of minutes I noticed that my check engine light was flashing at me. After that when the van was going up hills is really started to shake or missfire. I drove it the rest of the way home shaking and when I finally came to a stop in the driveway it stalled. I was quite sure it was a fouled plug or a coil.

Replaced all 6 plugs and wires.
Noticed Old Cylinder 3 plug was wet with gas.
Started it up, same problem, running rough.
Replaced all 3 coils. Started it up, same problem, running rough.

Borrowed friends code reader and it says misfire on Cylinder 3.
Checked plug and wire on cylinder 3. They are okay.

Swapped out ICM.
Started it up, same problem, running rough.
Cleared codes with code reader.
Then it said random missfire.
I then took it for a 5 minute drive.
Codes now read missfire on cylinder 3 again.

Any help with this problem would be greatly appreciated.

Other History:
New Battery Fall 2011.
New Front Bearings Spring 2012
New Front Passenger brake line Fall 2011
New Tires Summer 2010
Installed Class 3 hitch with brake controller Spring 2012.


Do you
have the same problem?
Wednesday, August 1st, 2012 AT 12:53 PM

1 Reply

Check your fuel pressure first as this can cause this problem if it's low. Then check compression on #3, if 20% lower than rest then there is aproblem with valve/piston. Checkfor a vacuum leak and finally take to a pro so they can check injectors or run professional cleaner through it.
Was this
Wednesday, August 1st, 2012 AT 2:12 PM

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