Recently my car has been awful starting in the cold. (09 SS Sedan) It's fully bolted, s256et turbo kit, etc.

Things I am familiar with:
I know my cat warm-up is still enabled, and I'm familiar with how it starts with this.
I also know my tune is not perfect, and probably needs some adjustment, but I'm also used to how it starts with this.

However, it just recently got much worse, and not coinciding with the drop in temperature. It originally ran ok with the cold temps. It's been below freezing in the mornings here for quite a while, and one day decent (not good because of the previously mentioned problems, but bearable), one day awful. Remote start is almost useless, as it usually dies 2-3 times. Once it stays running, it sputters, bogs down, almost cuts out, surges, etc. for a short time. It lasts about the same length of time as my cat warm-up would be, I think, only much worse.

The rest of the time it runs perfectly. Even before the engine is warm, it switches to running fine after it gets through this issue. I can't think of anything I messed with or changed that correlates to when this started happening. Can anyone on here think of what could be causing this?

 

Check your evap solenoid. You can start by just disconnecting it. Then I would be getting logging software and figuring out what's going on

 

I appreciate the idea. Unplugging did nothing, but I stuck a new one on anyway, just to be sure. No change

 

How old are the plugs and what plugs are you running? Given its not the evap it could be plugs starting to fowl, as they generally are bitches on cold start when they're going.

 

Good point, I guess I shouldn't overlook the basics. I did check to verify it's misfiring across all cylinders, but I guess all the plugs are probably around the same level or age

 

Change the plugs for new delcos. Will probably take care of your issue

 

You letting the fuel pump prime before you start it? I've noticed cycling the pump twice on really cold days helps.

 

I have been doing this and not noticing a difference compared to if I don't, but I will try doing it a couple times.

The strange thing is how when it was cold earlier in the year, I didn't have this issue, making me think something has changed or gone wrong. It's worth trying, as it may be a combination of issues

 

New plugs made no difference. I'm starting to get convinced it's an electrical/tune issue, though I still can't figure out what changed or made it start doing this all of the sudden

 

I just fixed another members idle here in the tune a week ago. You should get ur tune spot on first

 

I appreciate your input, as your reputation with tuning precedes you. I shot you a PM/email if you have time to check it out.

 

Thanks! I responded

 

Your fuel trims are likely so jacked up that when they aren't yet operating your car can barely run, then after the car being on for a little time they start coming into play again and adjust to make the car run better.

I'm just taking an educated guess, but it's a pretty educated one.

 

mine started rough starting right when i wanted to sell it, throwing no codes, got the tune dialed in which helped a lot, before the tune it would completely die, tune got it to stop dying but still started rough.

the day after i sold it it finally threw a code for the vvt solenoids on top of the valve cover, replaced it and now its perfect. took about a month for it to throw a code for anything....