Rough starting idle

[magimerlin]

And at cold start up the idle request is only 975. Sounds kinda low to me..

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[Gramps]

mistake

 

[magimerlin]

mistake

What's a mistake, or did yah post in the wrong thread?

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[Gramps]

Wrong thread

 

[magimerlin]

Anyone have an idea?

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[92rcsb]

Did this ever get sorted out? Trying to figure out the exact same issue with my truck

 

[Supercharged111]

My Vortec does this too, seems more like a misfire though that goes away. Rumpity rump idle with stinky exhaust usually means lean, lean can artificially induce a lope and I've had it happen to me a couple times. I find it hard to belive there is no IAT sensor, you can't have speed and density without IAT by definition as I understand it. It could be in the intake manifold itself, have another look into this.

 

[magimerlin]

Did this ever get sorted out? Trying to figure out the exact same issue with my truck

No it has not...

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[magimerlin]

My Vortec does this too, seems more like a misfire though that goes away. Rumpity rump idle with stinky exhaust usually means lean, lean can artificially induce a lope and I've had it happen to me a couple times. I find it hard to belive there is no IAT sensor, you can't have speed and density without IAT by definition as I understand it. It could be in the intake manifold itself, have another look into this.

Tbi trucks do not have iat sensors. No wiring for one, no computer pin out for one, no referance for one anywhere, no part listed anywhere for one on a tbi motor. I've searched extensively everywhere. The tbi motors in the gmt400 series truck just do not have one. If you'd like to search for one and can find even a referance yo one I'd gladly listen to what you find, as I've exhausted all I can think of. That includes, me looking up all tbi years on my computer at work, dealers, full(not a little Chilton book) dealer repair service manual, internet of course, other peoples trucks in the tbi era, alldata searches and wiring diagrams.

I'm kinda at a loss here...

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[92rcsb]

I just replaced the distributor and coil in my truck, it hadn't been running for a couple months. Chevy doesnt make a factory replacement dizzy anymore and I was unable to rebuild mine because it was already replaced by the previous owner with a cheap parts store replacement. I ended up picking up a pertronix billet dizzy (wasnt willing to shell out $530cad. For the msd replacement) and managed to get ahold of a new msd street fire coil for cheaper than a delco. I dont recall it having this cold start issue before, but as I said it has been a couple months.