Help! Please. Vortec missing at idle

CHEVYGUY

MEMBER
GMC C1500

I have a 99 ck1500 vortec 350 w/68000 miles. The problem shows up when the truck is at an idle it codes in p306 or cyl. 6 misfire. Im at witts end and out of ideas. I have changed plugs, plug wires, cap, rotor bug, #6 injector twice, checked wireing over several times. Could a sluggish valve be the cause or should I just let the cel come on and live with it. :( [Quote] It was like that when I got here :twisted:

3 Replies

BOB77

MEMBER
26 POSTS

Have you checked the compression on that cylinder? Should be 150 psi. Could be the intake or head gasket on that one cylinder.

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Wednesday, January 18th, 2006 AT 12:30 PM

CHEVYGUY

MEMBER
2 POSTS

I checked the spark plug and shows no signs of water burn or blister. There is no water in my oil or oil in my water. I will be compression and vacume checking it. Thanks. [Quote] If at first you dont succeed keep sucking till you do succeed.[/Quote]

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Wednesday, January 18th, 2006 AT 8:39 PM

DARRYL

MEMBER
61 POSTS

Hello: does that plug look any cleaner than the others, does it look any different at all than the others. You may have a vacuum leak at the intake runner or something causing a slightly lean burn in that cylinder. Possibly run water all around the intake manifold and stuff to see if the engine stumbles or anything. See if the plug has a dark spot on the intake side of the porcelin tip, possibly sucking a little oil and air in from the lifter valley
good luck
Darryl.

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Wednesday, January 18th, 2006 AT 9:00 PM