Only on cold starts the engine stumbles really bad about 5 to 10 seconds after start up almost like its choking. Then once it gets through that it runs as normal as ever. As soon as the car stumbles if you shut it off and restart the engine it does not stumble. Had a buddy say it sounded like the throttle body resetting.

Also still having issues with the surging boost at about half throttle(when getting on freeways and going up hills) any ideas on that as well would be appreciated.

Thanks guys

 

Automatic? GMS1 upgrade?

 

it is an auto but i dont have the upgrade yet.

 

Do you have any intake modifications? Do you ever get a check engine light?

 

no intake mods. Had a KN filter for a while but took it out and cleaned the MAF thinking that was the issue but no dice.

And never get any check engine lights.

 

Hmm. I had similar issues when I was tuning for a different intake. Before I was tuned the car would skew the long term fuel trims to accomodate the different intake. These remembered long term fuel trims would cause the car to stumble on cold start until the active short term trims kicked in to adjust in real time. Perhaps pulling the fuse for the computer to reset it now that you have swapped back to stock would help? The surging at part throttle seems to suggest something else though. Maybe bad purge solenoid? Maybe weak bypass valve? Hopefully, someone more expert than me can jump in here.

 

i was actually hoping to buy the forge bpv and see if that helped the situation but money is tight right now.

 

Wouldn't hurt to get one of the Forge Motorsports BPV. I have probably spent close to $2000 trying to figure out my surging issue....still no answer. If you find out anything, let us know

 

A new spring for the stock unit is not too expensive.

 

As a mater of fact....

I have an almost brand new DEJON BPV spring. You can have it for $10 bucks shipped. Let me know