How long since a tune-up? Any applicable mil codes? You can check those yourself. If it is only an idle issue, clean the throttle-body and idle air control.

Answered by JDL (expert)
14,417 answers provided

its not a astro van...i dont know how that got on there ...its a 4.3 v6 c 1500 pick up

Response from mcpherson1981
1 question asked

I see, the info is still valid. Let us know.

Answered by JDL (expert)
14,417 answers provided

it was just tuned up from the previous owner and he said it never did this until it was tuned up...im thinkin the firing order is wrong

Response from mcpherson1981
1 question asked

OK, below is the firing order.

165432

Answered by JDL (expert)
14,417 answers provided

what a bout a bad valve or piston???

Response from mcpherson1981
1 question asked

If you think you have a dead cylinder, check for a dead cylinder. You kill the cylinders one at a time, quickly, If the cylinder you kill has very little or no effect on the idle rpms, that cylinder is dead or weak.

What about the firing order? You seemed to think that was the problem?

Answered by JDL (expert)
14,417 answers provided