Hawk312

iTrader: (8)

I have a problem with a `98 Trans Am that starts up, idles up to about 2200rpm for about 3 seconds, then drops the rpms to about 600 and dies. If I keep starting it up, it keeps doing this same thing. If I give it gas, I can keep it running. As long as I keep it above about 2000 rpm, it is fine. But if I let off the gas, the rpm will drop to about 600 rpm, run rough for a second or two, then die. It seems with each start and giving it gas, the problem is slowly going away (about 10 starts). This makes me think it is related to the cold weather (it dropped into the single digits and is about 10º right now. I don`t think the problem is fuel related as the car was running very strong at WOT just before this, and I can smell unburnt fuel today. Could the cold affect the plugs this much? I can`t help but feel this is related to my other thread here:
https://ls1tech.com/forums/general-maintenance-repairs/844479-stumble-1500-2000-rpm-4th-5th-6th-gear.html
Any ideas.

302_5.0

have you done a tune up recent?...my car used to kinda do that

cam

iTrader: (9)

Maybe IAT sensor or MAF. Unplug them one at a time and run it this will let it go into limp mode so If the problem goes away and it runs okay swap out whatever one affected it. Full Throttle ( site sponsor ) sells brand new delco MAFS for 75 bucks or so. GOod luck

FreByrd

iTrader: (1)

My car did the exact same thing, turned out to be the intake manifold was not tightened down well. So i torqued all the bolts down in sequence and its been 2 cold mornings now and the car starts and idles just fine. I even sprayed carb cleaner all over trying to find a leak of some sort, an none so even that method failed. So give that a try, its free, doesnt cost you anything.

BTW, torque specs are 86lb in's.

I used autotap as well before and after and all my sensor readings were ok.


jason

02gtp4now

iTrader: (7)

i had an alero that would idle about 2000 rpm couldnt figure it out got pissed and revved the **** outa it and sure enough it fixed it, had to do it about once a day then once every other day until it quit. so my awnser is let it bump.