So I've had my focus for 3 1/2 yrs, pruchased brand new. Ive never had a problem, except for an OCCASIONAL rough idle (mostly with AC on) and a FEW random stalls at a complete stop (which ive seen numerous people on here mention, specifically with ATX). Nothing steadily recurring, and nothing major. Then tonight, i get in my car to drive home and the CEL is on. All I have on my car performance wise is a MBRP..which ive had for 2 yrs..never had a problem until now..so Im not sure what the problem could be. Guess I gotta take it in and hope I dont come back with a nightmare dealership story. wish me luck!