2018 GT PP1 10R80 fuel/fire issue

[Dawgvet06]

Morning, everyone,

My 2018 GT PP1 10R80 went through the 1-way clutch failure/trans issue earlier this year (history/service notes posted in this thread: https://www.mustang6g.com/forums/th...tions-to-harsh-or-no-shift-conditions.135463/)

Since getting it back, the trans has been fine, a little rough when it's cold on start-up, but otherwise good).

Driving last week, and I noticed when I was sitting at a red light that it seemed to idling really rough. RPMs were hovering around 400 but bouncing up and down, and it felt like one of my kids was kicking the bottom of the seat - at first I thought I though I just had the stereo up too loud. At the next red light I noticed that it was still rough, and it seemed a little sluggish when I accelerated. During the last couple of miles on the way home it was still rough, and I started getting an intermittently flashing check engine light. Parked it when I got home, ate dinner with the family, and then drove it to the dealership for drop off that night - it drove completely normally and didn't seem rough at all, of course.

Service department looked it over the next day. Test drove it - no problems, checked it for stored codes (none) and performed a crank trigger relearn on it with a normal post-service test drive.

Since then it's been fine. Service notes are attached below.

Any thoughts? I've been burned on the good old "software reset" before (see 10R80 thread), and I'm starting to feel like the car is a little bit of a basket case. The car has about 8500 miles on it currently and is almost exclusively driven in town for short trips. I will occasionally put the exhaust in sport or track mode, but I've been hesitant to put the trans in sport mode since repairs earlier this year.

I drive the car like an old lady because I'm worried about it breaking again, but that goes against every reason I bought it in the first place, but I also don't how software would suddenly "break" to cause this issue.

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[z6cyl]

Could be dirty air/bad gas/any number of one-off things.

This weekend go out, warm her up, throw everything in sport and accelerate WOT up some on ramps to the highway a few teams and see how she does. If it doesn't break you're probably good to go, I wouldn't stress about it too much - these cars are meant to be driven and you have a warranty.

 

[Dawgvet06]

Welp...

Same issue this morning on my way to work. Rough idling (RPMs jumping from 500-1000 sitting at complete stop with the car in normal drive mode, hesitant acceleration, and some surging with intermittent check engine light. Turned around and drove it home, and by the time I got there, the check engine light was staying on. Drove it straight to the dealership, had the service advisor sit in the car - she said she could feel some rough idling and also saw that the check engine light was staying illuminated. It's there for the time being. Hoping they can figure out what is wrong with the car.

My confidence in this car has been completely destroyed. Warranty or not, this is 3rd time it's been to the dealership this year (4th time overall), and I've barely had it two years with only 8600 miles on it. The first time (transmission), they told me it was fine, and 9 months later the one way clutch failed and the tranny had to be completely rebuilt (2nd visit). The 3rd visit (fuel/fire) they said everything was fine, and here it is back in the shop after less than a month with more of the same.

Full transparency - I've been a MOPAR guy since high school (4 total - 97 Dakota, 07 Charger, 12 Charger, and I still have an 01 Wrangler). The 18 Mustang is the first Ford I've ever bought. With the exception of the 19 year old Jeep that needs something fixed on it every year or two from just wearing out, I've never had issues with any vehicle like this Mustang has had.

Jim

 

[Dawgvet06]

I got the car back yesterday. Service notes included below.

It looks like my car was showing both the p0316 and p0308 codes. Based on TSB 18-2130, they reset the PCM and performed a neutral misfire correction relearn. After a short test drive, the p0308 code returned, and they replaced the spark plug for cylinder 8 and swapped the coils which cleared the code.

The car ran like butter this morning on the way to work. Honestly the best it's driven in months. Makes me wonder how long this issue was going on. I haven't seen any check engine lights other than what I reported in this thread, and I'm pretty attentive to it given my past issues.

I'm going to take it for a nice long shakedown drive this weekend.

For the PCM update and relearn, does anyone know how long/how many miles it takes for the car to adjust to your driving style?

Jim

 

[Dawgvet06]

So quick update with more to follow - my car went down with a misfire AGAIN last Friday. Back to the dealership - they called Ford Tech support who suggested changing some of the O2 sensors. When they did, they found water in one of the sensors and feel this is the cause of the misfire. I've gotten two different stories from them on how this happened - first (from my service advisor which I don't believe) is that it came from the factory this way - I think this is utter BS. But second - when I talked to the service manager, he said that the rubber O-ring could have failed or been damaged which let water into the sensor. Unless it was a defect from the factory, I haven't done anything to damage/remove the o-ring or sensor... BUT ... when they tore down the transmission for the one way clutch failure in January, they had to disconnect the sensors, remove the exhaust, etc... so I'm very curious as to whether the sensor could have been damaged or not completely re-installed properly at that time. With the heavy Georgia rain we've had off and on in the past month, I can believe that some water could have snuck it's way into a damaged o-ring on the sensor (we had a particularly heavy rain last Thursday, and the car started misfiring again Friday) and caused the issue.

I don't have the reports yet (they just called to tell me the car was fixed and ready for pick up this morning) - but the service manager said it was the sensor between cylinders 6-8 - which does make sense as last time they read a misfire on cyclinder 8 and changed the plug for it. I sincerely hope this is the end of the misfire problem for the car. I'll post the service notes later.

Anyone else have any thoughts?

 

[GuardEcoBeast]

They dont put o-rings on exhaust......

 

[Dawgvet06]

They dont put o-rings on exhaust......

Poor choice of words on my part - I know - just implying that with the extensive tear down and reassembly of everything, I am wondering if the sensor was damaged during the transmission repair.

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