2000 GMC Sierra

SWEEDEN5

MEMBER
2000 GMC SIERRA
V8
4WD
AUTOMATIC
155,000 MILES

Truck idels rough sputters when excelerated from a stop. Gets bad gas mileage. I was told problem was created from driving with a bad spark plug for a long period of time. Any ideas how to fix or troubleshoot?
Thanks

Friday, January 9th, 2009 AT 7:20 PM

3 Replies

SERVICE WRITER

MECHANIC
9,123 POSTS

Is there a check engine light on?
If so what codes?

What maintenance procedures been done the last 60,000 miles regarding performance?

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Friday, January 9th, 2009 AT 7:26 PM

SWEEDEN5

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2 POSTS

P300 the check engine light goes on and off

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Friday, January 9th, 2009 AT 7:43 PM

SERVICE WRITER

MECHANIC
9,123 POSTS

Okay, so we have a multiple misfire situation.
After we solve this you are going to want to have a de-carboning procdure done. The cat is getting coated with raw fuel and is going to melt it down it if this isn't solved soon.

Excessive fuel condition first leads me too think a faulty fuel pressure regulator. This can be diagnosed by checking the fuel pressure. If it is too high, then relace the regulator.

Do you need the spec on this?

Don't keep running this engine with the light flashing other than diagnosing!

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Saturday, January 10th, 2009 AT 7:30 AM