When the engine is cold, it does'nt idle properly. It will die unless you give it a little gas to keep it running. It also "surges" a little up to about 1500 rpm when it is driven while it is cold. After it warms up for just a minute or two, it runs fine. Any ideas?

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86 iroc, tpi, compucam, headers, pace-setter cat-back, stageII chip, afpr, air foil, filters, maf screens removed.

 

My car does something similar to this, I'll start it in the morning and it acts like it wants to die. If I don't touch the gas the rpm will go down to about 800 then go up to 1500, after about 15-20 seconds it idles fine and I don't have any problems with it except in the morning. I havn't pinpointed it yet, I think it has something to do with one of the sensors, just a wild guess, I've tried a lot of stuff. It seemed to help a little when I cleaned the throttle body, but no long term difference. I'll let you know if I figure it out.

 

Check your cold start injector. Actually, all the injectors.

Does it also start right up when it's cold (idle problems aside), but when it's warm takes a second or two of cranking?

 

Im having the same problem, surges and all. Once its warm, everything is fine.

She starts right up when its cold. And starts right up when its warm.

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No License, No Hope.

FILTERCHARGED BABY
http://www.crushed.org

 

I had the same problem with my 88 305tbi till the altenator died. no the car don't start period. oh well i got my 86 z28 now so the 88 just sits around. It would also do this when the car has been sitting for a over 5 hours id say. warm cold it doesnt matter.

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86Z28, 350 gm motor, Borg Warner 5 speed, hurst shifter, 3.73's, Edelbrock heads and carb, Edelbrock headers and cat back 3" all the way, 2 1/2" cowl induction hood, and K&N air filter.

 

my idle got a lot better when i got rid of the iac. you can just set your idle with that little idle adjustment screw.



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1986 Iroc 305 small block chevy getting modded now for speed

 

my car does the same thing it surges really bad when cold usually on second gear
but once it gets warm it will rearly surge,but it does it. and it usually happens around 2000 rpm.
another question what is the idle supposed to be at, when i get to an intersection it idles around 500 ,sometimes jumping to 750-1000. (its an 88 sc 2.8 mpfi w/t 5 spd. man. trans.)

thnx in advance

 

Have you gotten any cods from the Throttle Position Sensor?Mabey its gone bad or need s adjustment.My car has been acting up like yours has and I got the code.Friday I will fix it.

 

the Cold start injector is only used for a max of 8 seconds, so pretty much once the car is started, ur idle depends on readings from the Coolent temp sensor, Air temp sensor, and is controlled by the IAC, try replacing ur two temp sensors, and maybe ur IAC and things should really start working better.

and as far as the surging, as mine used to act funny when cold, would it kind of not go when u gave it a little gas, and would feel kinda maybe like the engine wasn't getting gas and then would all of a sudden take off? like u give it gas, it doesn't respond then all of a sudden it goes? if so thats what mine used to do, and replacing the CTS and Air temp sensor ( can't think of the name for it) helped the problem alot. as well as cleaning the IAC passages.

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- David
88' GTA 5.7L TPI MODS---> air foil, K&N, Shift Kit, 180* therm, TB bypass, Gutted CAT, Flowmaster 80 Series Muffler added to Unkown CatBack, Ported Intake

http://www.geocities.com/david_angel_16

 

I seems to be haveing the same problem with mine only its alittle diff. In the morning now that its getting cold seems the engine runs like complet crap sometimes(and i mean crap) it gets better as it warms up but still really sucks..have to really gas it to get it running right...but if i let it warm up then kill the engine and restart it..its fine...runs great then. Any ideas what could be causing this? I have thought about my timeing or maybe im having a fuel prob...im in thr process of doin a full tune-up as well as adding headers, cat and cat back system as well...and ideas why the car does this when its cold?? Thanks

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86 IROC 305 TPI
Gutted Airbox, Modified MAF, Cat Back Exhaust System