1998 Chevy Tahoe Spark Plug

1998 CHEVROLET TAHOE
155,000 MILES • V8 • 4WD • AUTOMATIC
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WSCHWEDLER
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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??
Oct 31, 2010 at 10:02 AM
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MERLIN2021
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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.
Oct 31, 2010 at 11:17 AM
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WSCHWEDLER
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The only Code I get is the for the fowled spark plug. I will try the Throttle Cleaner spray test as you suggest.

Thanks
Oct 31, 2010 at 11:22 AM
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MERLIN2021
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P0304?
Oct 31, 2010 at 11:23 AM
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WSCHWEDLER
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Yes, exactly
Oct 31, 2010 at 11:33 AM
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WSCHWEDLER
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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?
Oct 31, 2010 at 11:55 AM
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MERLIN2021
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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!
Nov 2, 2010 at 10:25 PM