Hey Guys,
2018 Mustang GT here, 6-Speed Manual with 20k miles on it. For quite awhile I have thought this car doesn't run quite right, it sounds terrible with light throttle application at low speeds. I've taken the car to two Ford Dealers.... one of them I went to 3x and the lead mastertech told me to go somewhere else and at another dealer they failed to follow through with their promises of looking at my car.
It's had a total of 4 trips to the dealer and every time they will not put the car on a lift, hook up a scan tool... NOTHING. I bought myself a scan tool and started running live data on the car. No codes, no faults.... BUT on the live data, I noticed my long term fuel trim is always pretty deep into the negative side.
On idle my Long Term Fuel Trim 1 is always at -3.9% and Long Term Fuel Trim 2 is at -6.25%.... when I was driving around Long Term Fuel Trim 1 got to -10.1% and Long Term Fuel Trim 2 is at -12.5%.
I'm not sure if that's too far into the negative or not, but it seems pretty far down to me. What do you think? What should I do from here?
(The Short Term Fuel Trim btw stayed right at about 0 the entire time).
Thanks for reading everyone!
Brian
The 2018 and newer 5.0L Coyotes have numerous problems. I've owned a few and they were my last Fords.
You can check the injectors, etc. but to be honest I would get a mechanic's boroscope and check out what the internals look like. You'll probably find something internal isn't running right.
Of course, don't expect Ford to do anything for you. This is what they consider good customer service:
@Mod_Man Unfortunately we have talked before about this car and you have been spot on every time. I have seen this video before and it's very shocking... but so believable. I mean this video is literally your typical Ford dealer experience. It's just hard to let go and I haven't done it yet. There just isn't anything out there I can afford and nothing comparable to this car at the price I got it for... I'm in a bad spot.
For some reason I thought the name was familiar. Man I'm sorry to hear you are still having continued issues. Trust me I know the position you are in very well. Hopefully your current problems can be fixed and you can start getting some enjoyment out of it.
Well it's obviously running rich could be weak injector somewhere leaking fuel pressure regulator could be lots of things but it is running way too rich. Try to find a pro like me to at least road test it and analyze the data while he records it as he drives it down the road
Thank you Scotty!
Scotty, I took the car to TWO authorized Ford Dealers. They both said it was a bad purge valve. They replaced the purge valve and the car runs exactly the same numbers wise. On the work order, it sounds like they didn't even think there was anything wrong with the car, but just did it for the heck of it. Both dealers hooked the car up the Ford IDS system (that's what they call their dealer level scan tools), and said the car looks healthy everywhere.
I guess they don't know how to work on their own cars, or just don't care enough to dig deeper into whatever is wrong with this car, unless it has a huge catastrophic failure.