P219A code comes and goes....
 

Ok..i did a search and found 1 thread where someone said they had the same problem but it wasn't truly addressed outside of the same "possible's" I read on the internet. I know how knowledgeable alot of you are with Coyote motors and tunes so figured I see if anything new was figured out since 2012.

Problems with diag...I bought this car from a Ford dealership with catless aftermarket exhaust already installed. Previous owner used to frequent here but seems to have dropped off...so I don't have a clue what tune it has....I'm sure it has one because he had the Boss 302 intake with larger throttle body (Which was removed when he sold it) along with the exhaust.

I cannot seem to pinpoint any kind of frequency to the MIL light coming on outside of lower temperatures...seems to be more frequent on chillier mornings.

Has anyone figured out for sure why this is happening?

2012 5.0 with 40K miles.

http://www.allfordmustangs.com/forum...else-have.html

Check this thread out should help you solve the problem.

Canned tune. The guy got a full tune and it corrected the problem.

Problem being I didn't purchase the tune so don't a clue who to contact for an update....guess I just have to purchase new and start fresh....

Any recommendations on which is the best? Looking for a 93 tune with Catless X pipe, Pyre axle backs and cold air intake...and if I upgrade in the future (planning on getting CJ intake) will they adjust the tune for me or does that cost? Or should I just wait till I get the CJ and then tune (could be a year or so)?

I'm data logging for a AED tune this weekend. Shaun has a great reputation for tuning the coyote I'm sure you won't be disappointed. Lund also has a large fan base so you might want to check him out as well.

I did they same thing, purchased used and had no idea on the tune. I went to HPP Racing for a full tune. You could give them a call and see what they say. I think I would get it done sooner than later because it's a check engine light. It probably runs in a "limp" mode with that CEL.

I was thinking the same thing but I'm still getting somewhat decent gas mileage...averaging 20 mpg by the dash...regardless I still need to get it fixed...as a state inspector it irritates the hell out of me.

20 mpg? I get 16.4 max on the dash and pump calcs similar. I'm only driving 12 miles each way though and have a heavy foot.

I also bought mine used, runs great but dealer where I bought it said it's tuned. Pype Bombs all that's been done that i can see. Guess I should dyno it and or figure out the tune thing.

I drive from Arlington to Carrollton for work...about 70 miles a day at 65 with cruise control on in the right lane...UNTIL I see a comparable vehicle to mine...then it's play time :)

It I reset the mpg while on the highway it stay consistently at 25.3 mpg..adding stop and go in traffic and stop lights drops it to 19 mpg.

Thats really what trips me out...because usually a MIL light is limp mode...on default settings and the mpg drops...but being its a a/f ratio codes it scares me that it's running lean that would explain the numbers...so I reset it with my state inspection machine whenever its on and it stays gone for about a week or two.

I hadn't thought about the lean angle. Yeah, that would scare me, too.

Did you ever get it figured out, or did you leave it?

Been driving with it like this....it comes and goes depending on the ambient temps....went away while it was warm for a week...came back this morning. Can't afford a tuner right now so I'll save up and buy it for the lifetime tunes in the future :)