I have a 2014 GMC acadia with 96,000. I started chasing a shudder that occurred during acceleration, usually between 25-40 MPH, about 2 months ago. Goodyear told me it was due to a bad upper control arm and tires. So they replaced the tires and control arm for $1100 and it didn’t fix the shudder. The power steering pump went the next week (which I’m sure wasn’t related but was another expensive fix at $970). I brought the truck back to goodyear who told me that the calipers, brake line, rotors and pads were to blame and needed replaced for another $1100 (mind you, my brakes are only 6 months old). I got a second opinion and only 1 caliper and brake hose needed replaced but afterwards, I still had the shudder. I then took it to a transmission specialist who told me the torque converter needed replaced, which I did for another $1600. The shudder finally went away but 2 days after having the torque converter replaced, I was doing 70 on the highway with the cruise control set and my 6 yo in the backseat. The car started stalling out and decelerated about 20MPH immediately. We almost got hit by 2 cars. The “service stabilitrak” and “service traction control” lights came on so I limped it to the breakdown lane and turned the car off and manually turned off traction control. I restarted the car and it took about a mile to get it up to 40mph. I got off the next exit and firestone threw it on a diagnostic but there were no codes. They pulled the fuses for the anti-lock braking and traction control systems. I brought it back to the transmission shop and they couldn’t find a code either. When they drive my truck with the fuses out, it runs fine but with the fuses in, the engine starts to stall out at highway speeds. So now I’m $4200 into this truck, have no traction control for the snow and have another repair that no one can figure out (and since this current issue, I’m burning through gas like crazy). I emailed GM but have gotten no response. Has anyone else ever had this issue?
I only have this to offer ( Stop going to Firestone and find an independent shop with good online reviews ).
GM is not going respond because you are out of warranty and you had the work done by a place not affiliated with GM . Also the chance of anyone else having these problems seeing this post is slim.