starts great, pull out of the driveway , mostly 2nd gear 2-3000 RPM, she starts to Hesitate/buck, so i give it a little rev and that usually would take care of it, today it lasted longer then before and this time computer threw a code and check engine light came on. car is stock except for K&n intake,06 with under 4k miles, dont have a code reader but I think I can go to pepboys and they would read it for me. Idle is ok, it doesn't stall when driving and I push in the clutch. yellow check engine usually mean emissions right? thats why i thought maybe a breather got plugged or something like that, I was told you can get a check engine light even if your gas cap is not on tight, go figure. but anyway it does the hesitation when you first drive it and it is not up to temp yet. oh and the battery is new