Cold Start issues

[oxfordgt]

When I start my car for the first time of the day it will stumble for about 30 sec and run lean. Any other start runs fine. What I have seen from datalogging is when cold on the cold base table commanding .89 my wideband gauge is reading right around 1.00. Which makes me think the maf xfer is off but once warm the STFT and the wideband are both reading .98-1.02 which tells me the maf xfer is good.

Really scratching my head on this one. Any suggestions?

 

[Catmonkey]

When you say stumble, do you mean when you give the car a little throttle when attempting to accelerate, it bogs? Depending on what PCM you have there are a lot of functions to richen the "accelerator pump" shot based on ETC. I solved some cold start issues on my GT500 using settings in transient fueling. I also increased my idle speed when ETCs are under 70*. A lot of the idle speed settings are time limited (kickdown timer), so you may need to lenghten the time settings in the tune.

 

[oxfordgt]

Stumble as in once the car starts rpm drops to about 500-600 for about 30 sec then goes to 950. Start up is set to go to 1500 rpm then decrease with increased temp. But never does. On hot start the idle increases at start up like it's supposed to then drops to 950 after about 15 sec.