Car wobbles when accelerating

[Juice]

What Im about to post is speculation, but I have experienced some wierd shit with my EPAS in the coyote swap.
You maybe feeling something the computers are doing for whatever reason.
Try disabeling all the nannies like traction control, that you can and test.
The fix could be as simple as reading/clearing any codes and resetting the modules. (Forscan) Like rebooting your pc when it misbehaves. lol
I call this phenomenon "computer confusion".

 

[Nikotopless]

What Im about to post is speculation, but I have experienced some wierd shit with my EPAS in the coyote swap.
You maybe feeling something the computers are doing for whatever reason.
Try disabeling all the nannies like traction control, that you can and test.
The fix could be as simple as reading/clearing any codes and resetting the modules. (Forscan) Like rebooting your pc when it misbehaves. lol
I call this phenomenon "computer confusion".

I’m not too savvy on mechanical/tech skills like you are lol. If it’s not too much to ask could you give me a step by step instruction on how to do that. I will try the traction control test

 

[DieHarder]

I guess the best way to describe it would be as follows…

I’d be on the highway, for example, have the car in 3rd gear, hit the gas full throttle and as the car picks up torque and speed it’s as if the car is suddenly being hit with an extraordinarily strong wind that “sways,” “wobbles,” or “veers” the car left and right like a very windy day. Subsequently shifting to 4th gear maintains this “wobble/swaying” effect so long as the speed is high enough but the steering wheel remains completely UNAFFECTED.

Something isn't right with the rear end... loose/bent/broken/misaligned it doesn't matter. Get it into a frame/collision shop or a Ford dealer for a look. Wondering if your LCA's/Differential have issues.

Other issue as discussed may be tires. They should be replaced... Have you checked them for rotation direction and installation; like being installed inside out? Even if not unidirectional many tires have an inside/outside orientation that must be followed. Suggest swapping front/rear tires and retest.

 

[Midlife Crises]

I’m confused. I look at the alignment numbers and think it’s all screwed up. The front is off by almost 1 degree of camber and the rear is off by more than one degree. How is that acceptable? I drive a live axel car and set the front camber and toe myself and there is no problem getting the camber the same on each side within one tenth of one degree. Obviously in speck is not good enough or it wouldn’t handle funny. The first thing I would do is turn the traction/stability control off and see if there is a difference in the feel. If that dealership is unwilling to adjust the left side of the vehicle to more closely match the right side I would find a front end shop that will. Also your tires have been subjected to some level of abuse and you say they are warn. Replace them.
just my thoughts.

 

[Robert Larimer]

They’re a legit dealership and replaced my entire motor for free so I hope they’d do their job fine. I just don’t understand how this happened right after a supposed wheel alignment was conducted

Did you buy it used from that dealership? Is that why it was under warranty? I don't think they are crooks but they may be unfamiliar with Mustangs. They must have done a great job on the motor since you have no complaints about that. There is a reason Mustangs had solid rear axles for so long. IRS is great when it is right, stick axles are pretty bullet proof . Get another opinion.

 

[Nikotopless]

I’m confused. I look at the alignment numbers and think it’s all screwed up. The front is off by almost 1 degree of camber and the rear is off by more than one degree. How is that acceptable? I drive a live axel car and set the front camber and toe myself and there is no problem getting the camber the same on each side within one tenth of one degree. Obviously in speck is not good enough or it wouldn’t handle funny. The first thing I would do is turn the traction/stability control off and see if there is a difference in the feel. If that dealership is unwilling to adjust the left side of the vehicle to more closely match the right side I would find a front end shop that will. Also your tires have been subjected to some level of abuse and you say they are warn. Replace them.
just my thoughts.

I genuinely appreciate all the help and feedback guys! Despite this issue seemingly eluding a direct diagnoses. I will definitely get on replacing the tires and will reach out for a second opinion. Do those alignment specs really seem so out of whack that it could be the culprit to this “wobbling” effect?

Update: So I took my car for a speed heavy ride and had my ABS light turn on my dash along with a message indicating “Service Advance Trac.” I turn the vehicle on/off and message goes away. Could this possibly have any relevance or relation to my problem?

 

[Juice]

Your service advance trac fits with my theory that it IS something with the computers.

Forscan (forscan.org) is a free program that runs on windows. Its can read and clear codes on ALL modules. You need to buy an ELM327 obd adapter with HS/MS CAN swithch. I prefer wired USB. WIFI and Bluetooth ones do work too. They cost around $25.

All I would do first, is connect to car with Forscan and read codes, nothing else just yet. With that advance trac issue, there should be codes. Post the read. Dont reset anything.

 

[Nikotopless]

Your service advance trac fits with my theory that it IS something with the computers.

Forscan (forscan.org) is a free program that runs on windows. Its can read and clear codes on ALL modules. You need to buy an ELM327 obd adapter with HS/MS CAN swithch. I prefer wired USB. WIFI and Bluetooth ones do work too. They cost around $25.

All I would do first, is connect to car with Forscan and read codes, nothing else just yet. With that advance trac issue, there should be codes. Post the read. Dont reset anything.

Much appreciated brother. I’ll need a few days to get that running, just made another appointment with the dealer for tomorrow morning. Today, as I was driving to work the “Service Advance Trac” light came on again and the Check Engine Light too. Smfh wtf is going on here. Car has 30k miles and I haven’t even had it a year

 

[Juice]

I would just tell them fix the advance track and check engine light this time.
I have a feeling it will fix the wobble feel.
Ask for a full list of codes found, just out of curiosity.
You may not even need Forscan.


My swag is: a wheel speed sensor issue. . (Scientific Wild Ass Guess)

 

[Seth Flandro]

Does it feel like your tram lining? Does it happen all the time, on every road? Maybe your dragging a break/ warped rotor?

 

[Seth Flandro]

Or maybe in the accident you lost one of the wheel weights or bent a rim

 

[Nikotopless]

I would just tell them fix the advance track and check engine light this time.
I have a feeling it will fix the wobble feel.
Ask for a full list of codes found, just out of curiosity.
You may not even need Forscan.


My swag is: a wheel speed sensor issue. . (Scientific Wild Ass Guess)

So I went to autozone real quick to get it diagnosed. Here’s what I got

 

[Juice]

Now that is an iteresting pcm code. No hard faults, but the pcm thinks the engine is making more power than it should. Leads me to think there is a tune on the car, not factory stock.
Yes I had come across that one personally on mine. In my case, I suspect my tune got corrupted.
Autozone cannot scan the ABS module, where the advance trac is.

 

[Nikotopless]

Now that is an iteresting pcm code. No hard faults, but the pcm thinks the engine is making more power than it should. Leads me to think there is a tune on the car, not factory stock.
Yes I had come across that one personally on mine. In my case, I suspect my tune got corrupted.
Autozone cannot scan the ABS module, where the advance trac is.

You’re the man dude! I’ve been wondering about my car being tuned! Had a whole motor replaced because of a cylinder 8 failure! Could that have been the tune? I bought the car at 9k miles and it was definitely tuned but the dealership told me it was bone stock, but I can rev past the limiter to 8k. This is the second Coyote GT I’ve had and my previous one had no problems and definitely was not as fast as this one.

What’s the best course of action with a corrupt tune? I don’t know who tuned it, how it was tuned etc… How can I retune the car or set it to factory settings?
Btw are you on the East Coast? I live in NJ. I don’t mind paying you for your time if you live nearby

 

[Juice]

#8 failure is a known issue, it is the cylinder that fails first. I know good tuners address this by taking extra timing away from #8.
If you have the factory airbox, have the dealer reflash it to stock. Assuming you did not get a handheld tuner with the car?
If you have an aftermarket 'tune required' CAI, and the dealer reflashes it to stock, it will run like shit, or maybe not at all.

 

[Nikotopless]

#8 failure is a known issue, it is the cylinder that fails first. I know good tuners address this by taking extra timing away from #8.
If you have the factory airbox, have the dealer reflash it to stock. Assuming you did not get a handheld tuner with the car?
If you have an aftermarket 'tune required' CAI, and the dealer reflashes it to stock, it will run like shit, or maybe not at all.

Just spoke with the dealership attempting to find the previous owner and the car was purchased at an auction. I wasn’t given any “handheld tuner” and the dealer didn’t even know the car was tuned. I’m at a real standstill here and don’t know what the best solution here could be? Should I get it retuned instead of reflashing it back to stock? Is there anyway to identify the tune? Is there anyway to have the car relearn the tune properly? Will a KAM reset help? I’m at such a loss here bro and I haven’t had the car for over 6 months. I posted a picture of my engine below and I definitely don’t have a stock CAI smfh

 

[Juice]

Tunes are pretty much unreadable by most tuning software.
HP tuners is the only one that reads and edits the actual tume as read from the pcm.
I would have dealer reflash to stock, if and only if you have the stock airbox.
No way I know to tell what was used to flash it.

Looks like you are running a jlt tune required intake. Do NOT reflash to stock, it will not run.

 

[Nikotopless]

Tunes are pretty much unreadable by most tuning software.
HP tuners is the only one that reads and edits the actual tume as read from the pcm.
I would have dealer reflash to stock, if and only if you have the stock airbox.
No way I know to tell what was used to flash it.

What is a “stock air box?”

 

[Juice]

The factory air intake that was swapped out for that open element air filter setup.

 

[Nikotopless]

The factory air intake that was swapped out for that open element air filter setup.

Nope, was given nothing but a set of keys and the car. Would replacing the air filter set up to factory help? Can I just buy another tune or something?