2000 silverado high /rough idle when cold
#1
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2000 silverado high /rough idle when cold
ok more troubles again
2000 silverado 4x4 4.8l. when its cold out and only when the truck sits over night , when you first start it up it revs to about 2-2500 rpm then drops and stalls. does this 2 ir three times then runs fine. no codes were showing. its been doing this for a few weeks. then the other day I had a
p0306 code. i replaced the coil plug and wire and the IAC valve. started it up and it ran fine. drove about 30 miles and all good. went out this morning and it revs back up and dies again. got me stumped. had it to a shop and they thought it was the iac valve to. he says my intake gasket is fine but i am sure he only checked it in his shop
after it was warm. possible the intake gasket???
any help would be appreciated. thanks
2000 silverado 4x4 4.8l. when its cold out and only when the truck sits over night , when you first start it up it revs to about 2-2500 rpm then drops and stalls. does this 2 ir three times then runs fine. no codes were showing. its been doing this for a few weeks. then the other day I had a
p0306 code. i replaced the coil plug and wire and the IAC valve. started it up and it ran fine. drove about 30 miles and all good. went out this morning and it revs back up and dies again. got me stumped. had it to a shop and they thought it was the iac valve to. he says my intake gasket is fine but i am sure he only checked it in his shop
after it was warm. possible the intake gasket???
any help would be appreciated. thanks
#3
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hi. no idles good and runs good. takes about 5 tries when starting first thing in the morning. the first five or so start are all the same. it fires right up but revs right up to between 2000-3000 rpm then drops right down to below 500 after about 5 secs then sputters and dies. some times it will keep reving up and down... really high to really low for a minute then will run good... this is usually about the 3rd or fourth start up after the
first few stalls.
all new o2 sensors. new maf. new iac. cleaned throttle body. new plugs a while ago. and not throwing any codes. other than the p0306 the other day but ifixed that one.
got me stumped and obviously my mechanic to.
first few stalls.
all new o2 sensors. new maf. new iac. cleaned throttle body. new plugs a while ago. and not throwing any codes. other than the p0306 the other day but ifixed that one.
got me stumped and obviously my mechanic to.
#6
Senior Member
True Car Nut
sometimes when the battery is old or the connections are bad, the voltage will go down while cranking cold enough to reset the learned values, but normally you can kind of hear it cranking slow.
normally you would test a vac leak by letting the engine stabilize and some carb cleaner and listen to the engine but may not work if it seals after the engine warms a little. i might try it any way, do you have a scan tool with live data?
normally you would test a vac leak by letting the engine stabilize and some carb cleaner and listen to the engine but may not work if it seals after the engine warms a little. i might try it any way, do you have a scan tool with live data?
#7
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no I don't have one with live data I don't think? it gives me freeze frame data but I don't really understand it, as long as it gives me the codes that'* what I can handle lol.
it isn't throwing any codes yet anyways, maybe I should just try and change the intake gasket?
it isn't throwing any codes yet anyways, maybe I should just try and change the intake gasket?
#9
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I am not sure what data it shows for sure but I will check tonight, I did delete all the codes on it Friday when I fixed the p0306 I had, do I just hook up the scanner and start the engine then to show the feul trim data? or will it be stored in there already