2000 Chevy Silverado severe misfire

HEILMAN

MEMBER
2000 CHEVROLET SILVERADO
V8
4WD
AUTOMATIC
175,000 MILES

Severe misfire under all driving conditions. Have replaced #6 injector, cleaned and cleaned other 7, checked all 8 coils, replaced plugs and wires, replaced 1 o-2 sensor, replaced ecm, and intake gasket had small leak\replaced. Sometimes truck runs fine.

Friday, February 5th, 2010 AT 6:00 PM

3 Replies

JACOBANDNICKOLAS

MECHANIC
110,176 POSTS

Is the only code you are getting a random misfire? Have you checked or replaced the crank sensor? Control module?

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Friday, February 5th, 2010 AT 6:03 PM

HEILMAN

MEMBER
1 POST

I have replaced control module (ecm). What where is the crank sensor?

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Friday, February 5th, 2010 AT 6:11 PM

FACTORYJACK

MECHANIC
4,159 POSTS

If it is a 4.3, it is in the lower portion of the timing cover. If it is 4.8, 5.3, or 6.0 it is on the right rear of the engine block, above the starter.
Has the misfires ever been graphed to determine which cylinder(s). It could be possible that you have a degrading cat causing a whole bank of cylinders to misfire. When there is no airflow, the particles of monolith settle in the bottom. As exhaust passes through, it picks up the particles and starts resticting exhaust flow. This restriction will result in misfires, as no air can be drawn in for adequate combustion.

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Saturday, February 6th, 2010 AT 1:44 AM