Has anyone had this problem?

My daily, a 2001 s10, 4.3 w/ auto, it started running pretty rough at idle then progressed into feeling as if its missing when the engine isn't under a pull, like if you have your foot barely on the gas to just kep it at road speed it will feel and sound as if its missing, but it doesn't do it as long as you are picking up speed or having to push the pedal at all, it will run just fine then. Now the rough idle has a bit of a backfire to go along with it. Cn anyone think of what can be causing this

tbi or cpi?

cpi

its hard to diagnose those simply b/c the CPI was such a touchy motor.. 1 little thing, it wont run right.

a friend had one that missed like you said yours does.. it ended up being the coil wire starting to burn through from sitting on the manifold.. he also changed the coolant temp sensor.. it helped.

but your problem could be something else.. does it throw any codes? if so, get em read to you at autozone for free.

the problem I'm having there is that a little over a year ago the truck had lightening run in on it while sitting next to fence during a storm. it didn't affect the truck running at all but all the lights in the dash came on. Then i put a power prgrammer on it, and tried to see if it would read the codes with the programmer but all it says is that it won't contact the PCM

I think I'm screwed

i'd find an ECM and try that.. at least the data port would be back online.

i had a 1993 blazer with a cpi.. it would miss like you are talking about.. every once in awhile, i thought iwas just imagining it b/c it wasnt constant.. then it just died on day like you turned the key off and while coasting, make a short rev and took off again (refired.. but i never turned the key).. after a LOT of research on the CPI motors, i got rid of it very quick.. it was in the shop a few times to get it fixed.. i had over 600 in shop bills on it and it still randomly just shut off..

hope you can fix yours, but i'd get a new ECM and get the data port back online and go from there.

sounds like the idle air port is blocked up in the throttle body
it gets carbon build up in their
since at idle the throttle plate is closed, air has to get into the motor some how

i had the 4 cilinder one and i had the same problem and all i did was change the fuel filter and plugs and wires and that fixed the problem

I've changed the idle air snesor recently, can't remeber how long ago though, been less than 6 months, do you think it could be farthr into the throttle body to be causing it Originally posted by joakwin



sounds like the idle air port is blocked up in the throttle bodyit gets carbon build up in their since at idle the throttle plate is closed, air has to get into the motor some how