1998 Chevy Silverado Engine Misfire Code

Tiny
GRYANJUDD
  • MEMBER
  • 1998 CHEVROLET SILVERADO
  • V8
  • 4WD
  • AUTOMATIC
  • 70,000 MILES
My check engine light came a about 3 months ago and I had the code checked and it said cylinder 5 was misfireing. I changed the spark plugs to the recomended plugs and changed fuel fliter due to the age of the truck. It still says same engine code. Cylinders 5 & 7 plugs are extremley coreoded and I have to clean them monthly, all other plugs are perfectly clean. After I replaced the fuel fliter I have started to shoot black soot out of the tail pipe. What do you think would be causing this? CO detector, piston rings? Anything would help
Thursday, January 21st, 2010 AT 11:55 AM

5 Replies

Tiny
DOCFIXIT
  • MECHANIC
  • 18,828 POSTS
Check compression on 5-7
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Thursday, January 21st, 2010 AT 12:05 PM
Tiny
GRYANJUDD
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  • 3 POSTS
I have allready checked. 5 & & have 50lbs and the other have 118 if I remember right.
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Thursday, January 21st, 2010 AT 12:42 PM
Tiny
DOCFIXIT
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Well there is your answer should be @145+ 50psi is not going to ingnite and 118 barely.
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Thursday, January 21st, 2010 AT 1:17 PM
Tiny
GRYANJUDD
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  • 3 POSTS
So what is the first thing I should do to fix it?
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Thursday, January 21st, 2010 AT 1:41 PM
Tiny
DOCFIXIT
  • MECHANIC
  • 18,828 POSTS
A cylinder leak down test would tell if burnt valves or rings. Otherwise need to pull head check valve seats and valves for warpage.
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Thursday, January 21st, 2010 AT 1:50 PM

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