Good Morning everyone!
This is my first post on this forum I believe. So my girlfriend bought this 2009 SS/TC a few months ago and so far it has been great. We've had a small issue with the downstream O2 sensor and the Rr TPMS, but other than that it's been good... Up until this morning. She woke up and went outside to start her car to warm it up, and it struggled to stay alive. As soon as she turned the heater on it got worse, and then she tried to give it some gas and it died. I think I may have it figured out why this is happening, but I wanted to know if this happens to you guys too? We live in southern Idaho, and I'm fairly certain it got down to about 5 degrees

 

They can be stubborn to idle well in the cold. I would recommend you let it warm up before driving. Is the car running a factory tune? How many miles on the car? I'm guessing the valves have probably never been cleaned and they will hurt idle performance.

 

weird, I live in Manitoba Canada and I could start mine no problem up to -30c after that it struggled a bit, but anything up to that it fired right up and had no issues running. What it could be, which was the issue I had with my truck when it got cold is, ur battery is possibly toast. my truck started fine till the cold, then it struggled, and finally I needed to boost it. went and tested my batt, it had 1/3 the cranking amps it should have, so I got a new one, problem solved. go test ur battery. And no, u cant just put a multimeter on it, u need a special tool. can do it at probably any automotive store

 

Ya mine always starts up easy too. It's been around -20C this week and no issues. It grunts quite a bit but it never hesitates.

 

Yup. -30 Celsius and mine starts fine.

Try priming the fuel pump twice. (Turn key to ignition on wait for the pump to stop then shut it off and do it again, then crank.)

Are you using good fuel? Could also be the Evap Purge Solenoid.

 

Any engine lights on? coolant temp sensor not reading right will mess up the fuel trims . If you can get live data read it vs actual temp. when you give it WOT thats clear flood and removes fuel so I'd lean towards that possibly over fueling for the inproper reading maybe

 

Had a similar problem. Never threw a code, but I had a pending code for the Evap System. Remove the Evap purge solenoid and try to blow through it. That's what happened to mine. It was stuck open. It's a $15 part and depending on how many miles, you might just as well replace it. Mine had 92k on it. I could tell a difference in average driving and boosting after replacing it. Everything felt much smoother. Also probably wouldn't hurt to clean your valves.

 

Sounds to me like the Evap purge solenoid..

 

Thanks for your suggestions guys! We did some more searching after replacing the battery to no avail. I found a vacuum line that had been rubbed through and cracked. That solved the problem with starting, but now it won't boost past 5psi and falls on its face around 4500rpm. Any ideas?


--Nathan