2G Choppy idle on first start up

[eclipsemf]

I just got done getting my 2g gsx ready for inspection, Replaced o2 sensors, did new hard IC pipe, fixed an exhaust leak and rebuilt the 14b on the car, Nothing else has changed with it and only had bolt ons right now. I drove it 200ish miles after all of this was done with no issues, now when I start the car for the first time in the morning it stumbles at idle dropping to as low as 200rpm and is running super lean on the wideband so lean it just shows ---. Once I put it in gear and drive just enough to get it in to 2nd its fine and goes away for the rest of the day and runs great. I have done a Boost leak test and thats good and it wont even throw a check engine light, turbo is still great.

I just cant seem to figure it out and its just getting super annoying. I do have a basic scan tool I can pull some info from if any of it will help. Any advice or thoughts are wlcome ill try anything at this point. Car has just over 100k on it.

Thanks

 

[BLACK'98DSM]

So this only happens when it's cold? If you start it and the temperature is warm then it's fine?

 

[eclipsemf]

So this only happens when it's cold? If you start it and the temperature is warm then it's fine?

Cold as in only if the car hasnt been started that day, outside temperature doesnt seem to have an affect on it yet. Once I drive it during the day and come back out to drive it its fine

 

[BLACK'98DSM]

Yes, I was referring to the engine temp, not the climate

 

[eclipsemf]

Im from New England so temps can be 20 at night and get in to the 70s during the day right now so wanted to make sure that was clear

 

[1990TSIAWDTALON]

Fuel pressure coming right up as soon as the car starts?

 

[Vegas Smith]

Check for a check engine light (pun intended) and report back. I wonder if you have an FIAV air leak. Sometimes an FIAV can cause a vacuum leak at certain temps. Is yours blocked or modified?

 

[eclipsemf]

Fuel pressure coming right up as soon as the car starts?

I have to check on the fuel pressure, that actually kinda seem like the issue. If I rev it around 2000 rpm its usually come out of it then once driving its gone. ill have to check that when i head to the post office later.

Also no check engine light. I have driven it about 250 miles so if it was major something should have thrown already. As for the FIAV everything there is stock and untouched

Also with the fuel pressure this car sits all winter so there is a chance it could be a leaky injector allowing some air to get in to the fuel lines that would cause the hesitation until it all clears out

 

[eclipsemf]

Just finishing this off here. I finally got a check engine light to come on after about 600 miles of this! Turns out it was the upstream o2 sensor was being a little funky. Should have the new on here in a day or 2 and will be good to go!