Bought a 2014 mustang gt 4 weeks ago. Driving home from work 3 weeks ago and a flashing cel came on. Didn't actually notice any misfire. Took it to the dealer, and they did a relearn. A couple weeks without an issue, so I decided to put on a intake, exhaust, and tune. 2 nights ago, driving home from work, get a flashing cel again. This was after I downshifted and passed a couple cars. When I noticed the cel I gave it some gas to see if I could notice a misfire. This time I noticed a misfire. I've read that the u2 sensors are kinda sensitive, could it have been because the car wasn't up to full operating temp? Any suggestions would be great so I have something for the dealer to look into. Wanna get this resolved as soon as possible so I can continue to mod this beast, without having to go backwards lol. Thanks ahead of time.

 

O2 sensors*

 

Hi Emerald516,

Welcome to the forum! My name is Deysha with Ford Service and I recommend you bring your vehicle in to your Ford dealer for diagnosis again. Then, PM me with your VIN, dealer, mileage, full name, and best daytime number so I can escalate this to the customer service manager for your area.

Deysha