[Nikotopless]

Greetings everyone!

So I just received my 2015 Mustang GT PP back from the dealership after completing a wheel alignment, replacing all spark plugs and most importantly, installing a new motor and replacing the old one that had a cylinder 8 misfire with no recourse of fixing.


The day I picked my car up from the dealership for the motor replacement, the car now “wobbles” consistently during hard accelerations at high speeds and RPM’s (Ex: 3rd-5th gear - 4kRPM<xRPM) for the first time. For example, if on the highway and accelerating (full throttle) with high RPMs the car seems to “wobble” in a left to right fashion. In other words, it feels slightly similar to a fishtail, but when I let go of the throttle the car starts stabilizing. I was wondering if the dealership possibly installed the engine mounts incorrectly (Engine has strut bar), if my uneven exhaust tailpipe is causing the car to thrust asymmetrically (rear end collision caused passenger side tailpipe to hang lower and unevenly) or there’s any other input, advice or reasoning someone can can help out with.

Additional Info

-Wheel Alignment was completed at dealership

-Car was moderately rear ended causing uneven tailpipes (passenger side hangs lower, but it doesn’t fluctuate or move around)

-Had a serious car accident (hit and run) a few months ago and had the entire suspension replaced, but never had any issues until now

-Tires have low tread but not low enough to destabilize a vehicle like that

 

[Braindead]

Shouldn’t be alignment but sounds like tires working against each other as with mismatched “toe in/toe out”. I’d say more likely unbalanced tire, threw wheel weight? No expert by any means but after these things happen time after time?

 

[Nikotopless]

Shouldn’t be alignment but sounds like tires working against each other as with mismatched “toe in/toe out”. I’d say more likely unbalanced tire, threw wheel weight? No expert by any means but after these things happen time after time?

I just discovered a lug nut missing on the passenger rear tire. Could that be the culprit?

 

[crjackson]

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[Braindead]

Yes indeedy, a missing lug nut, even on rear. Check all nuts ASAP. Yup they forget to tighten sometimes and spin off, especially PASSENGER SIDE (had backwards earlier/rlb). Chrysler used to have left handed thread so they’d twist on tighter if lose. DRIVER SIDE will also tighten w/right handed threads. 😳 Our Fords are all the same threads.