I have an 02 wrx. Slightly moded. (VF34, sti pinks, walbro 255, invidia headers, turbos xs catless upipe, invidia V3 catless down pipe, invidia down pipe back, perrin induction pipe, samco IC hoses, turbo xs xl top mount IC, perrin fuel rails, turbo xs utec, turbo xs boost controller and i just recently had the car tuned by F1dyno, 308 whp) when i start it cold it idle so so bad but as soon as the coolant gets to operating temp it idles fine. No faults stored in the ecm. Checked car over throughly for any air leaks no leaks at all. Just recently installed new coolant temp
sensor just grassping for a fix and still nothing. Did a compresion check everything ok. removed and cleaned idle air control valve nothing. the car also somewtimes boggs and coughs if you chop the throttle and bring it off idle. The car was just recently tuned and i goes awsome the guys at F1 Dyno in Maine do a great job. But whne i brought it to them i wasn't able to show them the bad idle because i had just drove the car from Ma. and they put it right on the dyno. It never got the chance to get cold. But this shouldn't be a tunning issue right? I thought the stock ecu handles cold start and idle and open loop stuff? I'm bringing the car back up to them in 2 weeks. I'm gonna got up a day early and let it sit for the night so they can see what i'm talking about. well enough blabbing. What i'm really trying to find if anybody has any info that would possibly help me with. I'm probably go have to bring the car to subaru and have them use the factory diag equipment, select monitor or whatever its called. Thanks for listening. Also if you live in the New england area and you need a good tunning facility give F1 dyno a look. They spent alot of time on my car and there pricing is very good. F1dyno.com

 

f1dyno.com needs to retune it

does it idle up at cold start

you need to look at the TGVs also

sorry i can tell you what to do but im in so cal and 50* is cold start for us