LS2 Pontiac GTO

Im having a bit of a idle issue with my car. I went to start it up this morning an it ran fine for a minute or two then the idle started going up and down like it was trying to find its idle speed. Then my SES light started flashing so I turned the motor off and scaned the PCM and got I believe it was a P1426? code, it had to do with the teft system. I cleared the code and started it back up and it died twice. when I was leaving work when I put the car in R it surged a bit then died when I switched to D. It started right back up. As I drove it around the idle did get better. Now when I drove it home last night I didnt have this problem. I was also stuck in stop and go traffic and the car idled just fine. How long does it take for the car to learn the tune? BTW my idle is set at 600.

2004 GTO A4

Kooks 1.75" LT's w/Cats
K&N AirCharger
Borla Cat-Back Exhaust
SLP P/P Throttle Body
EDC Cam 220/224 .596/.589 @113 LSA
Patriot Gold Dual Springs
Comp Cams 7.4 Pushrods