random misfire on #7

[clintmc]

Can anybody please help? I have a 1999 4x4 silverado and I have had a random misfire in cylinder 7 for about a month now. I have changed out the plugs and wires and even that coil. Has anybody heard of this and can give me any direction?

Thank You

Clint

[internic]

if you are sure the coil is producing spark to the plug, you could swap the #7 cylinder injector with a different cylinders injector and clear the code then see if the other cylinder pops up for random misfire, that means your injector is clogged and making the cylinder run lean.

[clintmc]

Thank you so much for that info. I am new to this fix it yourself so how can I tell if the cylinder is firing?

Thanks Again
Clint

[skipr]

If #7 wasn't firing at all, beleive me you would have more than just a misfire. You would lose about 40% of your power and it would run horriably throughout the whole rpm range (not just idle). Are you getting a P0307 DTC?

[clintmc]

I do believe that was the code but the main problem is not at idle it is on accel. at about 2000 RPM. Could that be any kind of vacuum leak or exhaust leak?

Thank you

Clint

[skipr]

Originally Posted by clintmc

I do believe that was the code but the main problem is not at idle it is on accel. at about 2000 RPM. Could that be any kind of vacuum leak or exhaust leak?

Thank you

Clint

I would have to no to both of those. Because it's only 1 cyl. that is affected. I would suspect bad or clogged injector, or something more severe like a burned valve. A compression and leak down test would give you a definite anwser on valve or ring problems.