First start in the morning the car runs really bad, missing stumbling wants to stall but doesnt. Does this for maybe a minute or so than smooths out. Im thinking i mite have a bad upstyream oxygen sensor. I do believe that it runs like crap first thing then when it goes into cloosed loop it smooths out, which is why im pointing at the O2 sensor.Anybody else ever had these symptoms and what was the fix. any thoughts/advice will be greatly welcome. Thanx guys-Gary

 

I had that happen about a month or too ago , when it was cold outside.

I did a video, is it similar?
http://s193.photobucket.com/albums/z...TC_startup.flv

Mine was doing it for a second or 2 and it was fine, or would stall and was fine after the restart...

Some talked about the cam phasing.... i cant say if its related.
My car was fine in warmer weather but i got a CEL 3 weeks ago, got it to the dealer and it was bad spark plug on cylinder 2 and 3.

May be it was just the plugs..

 

If the 02 sensor was flaky, it would do it in closed loop, not open loop. It runs off the base LTFT tables until closed loop. Any mods on it? How many miles? Need input.

 

29k miles trifecta dual stg tune, hahn 3Inch catless turboback exhaust, hahn cai, injen hot side pipe. Just put plugs in it about 5k miles ago. It has nothing to do with air temperature, i meant when the car is cold after sitting overnite. I thought i had carbon issues so i ran some seafoam through it and it was fine for about 5 days, then it started doing it again. Was thinking i got scammed on gas, ohio does not require octane ratings to be tested, so selling 89 octane in the 93 octane nozzle is completely legal here in ohio because the dont check it. Need more lemme know, this is starting to **** me off

 

The downpipe caused it. Give it a little while. It'll go away.

 

I ran into an issue about a month ago that was similar.

Car would start up but then the idle would bounce from 1500 down to 500rpm for about 15 seconds before settling down. No codes in the computer. Always did it cold, no problems warm.

I cleaned the mass airflow sensor even though I'm running the oem filter. And I unhooked the batter for a couple hours. Car has been fine ever since.

 

My car does this same **** when its cold

 

Nahh i dont think i had the exhaust before i even had the car, its got 29k on it as well. Thanx for your input . Keep the ideas coming pleeze.

 

Probably the Evap purge solenoid stuck open. It allows a little bit of evaporated fuel directly into the intake, causing uneven idle (seeks) until the car is warm. May or may not trigger a CEL. Mine didnt the first time it failed. The second time it failed it triggered a code. Once it is replaced, the car runs like new again.

BTW that is two failures in 40k miles. It should be warrantied, since its a cheap part and takes the dealer like 10 seconds to replace it. Not worth their time to argue the replacement.

 

this happens to me every few days it seems. even the past week or so when its been fairly warm in the morning. about a month ago or so the car did stall, but that only happened once. most of the time it'll just idle up and down from 1500-500 like u said for about 5 seconds or so and then level off. i was wondering myself what the problem is.