1998 Chevy Tahoe Spark Plug

WSCHWEDLER

MEMBER
1998 CHEVROLET TAHOE
V8
4WD
AUTOMATIC
155,000 MILES

Our 98 Tahoe continues to burn the #4 cylindar Spark Plug. It lasts around 1 to 2 thousand miles. The Porclin around the electrode gets small cracks around it. I feel that a lean fuel mixture could cause this. What would cause only one cylindar to continue to do this?

Sunday, October 31st, 2010 AT 10:02 AM

6 Replies

MERLIN2021

MECHANIC
17,250 POSTS

Lean burning is caused by either a vacuum leak or a bad injector, Any codes stored? Service engine light on? Check the intake manifold gasket. Get a can of spray throttle body cleaner, and spray around the edge of the manifold, a change in idle speed indicates a leak.

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Sunday, October 31st, 2010 AT 11:17 AM

WSCHWEDLER

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4 POSTS

The only Code I get is the for the fowled spark plug. I will try the Throttle Cleaner spray test as you suggest.

Thanks

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Sunday, October 31st, 2010 AT 11:22 AM

MERLIN2021

MECHANIC
17,250 POSTS

P0304?

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Sunday, October 31st, 2010 AT 11:23 AM

WSCHWEDLER

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4 POSTS

Yes, exactly

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Sunday, October 31st, 2010 AT 11:33 AM

WSCHWEDLER

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4 POSTS

I sprayed around the intake manifold with Carb Cleaner, no increase or change in engine speed. This engine has a throttle body, could it be causing the problem?

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Sunday, October 31st, 2010 AT 11:55 AM

MERLIN2021

MECHANIC
17,250 POSTS

Try unplugging the #4 injector, listen to see if the engine momentarily drops speed 100 rpm and recovers, if no change, injector is probably the problem. Also, check the ground strap at the back of the cylinder head, remove it and clean the end and the block attaching area, use emery cloth, get both surfaces nice and bright, then re attach it, then cover it with RTV. This is a known problem on GM truck!

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Tuesday, November 2nd, 2010 AT 10:25 PM