Engine light on, sluggish acceleration, veh warmed up, 38deg outside

I had the same issue with my '07 Amanti. Was about to take it to dealer, then remembered that I filled up with gas the day before. Stopped (turned off) the car, and sure enough I had not put the gas cap on correctly, it was slightly cross-threaded. Took it off, put it back on, and the car started and ran normally. The check engine light went out in a day or so.

Take a look at this information on the check engine light: http://repairpal.com/check-engine-light You'll need professional diagnosis and repair.

it could also be your tps (throttle posistion sensor) the same thing happened on my 05 amanti and all i did was pop it out clean it and put it back in try that and it should clear up your check engine light