[Azerlazer26]

Originally Posted by DarkMaroSS

Well, mine is a 2018 SS with the A8 and is having this exact same problem. Hi everyone. I'm surprised this thread/issue started in 2016 and still it is present on 2018 vehicles; quite disappointing to say the least.

Anyhow, it started when it had about 8,500 miles more or less, to the point it started to get more apparent, to stop thinking about road conditions and stupid things like that. I take it to the first flush at 9,300 miles to a Chevrolet dealer in Broward County, FL, and they got it done no problem. The adviser I work with is more than knowledgeable and helpful so to me this is clearly not the issue as he always goes well beyond what I can expect. Anyways, I was told to wait about 200 miles and if so bring it in, but I thought of waiting a bit more and the issue never went away but simply was felt less for a few miles and went back. Today, I take it back for them to do the diagnostics required by GM and apparently everything came back normal as I said it would.

The issue in my car only comes up after driving on the highway for about 10-20 minutes or more, and around 1,250 rpms at 35-65 mph and then at high speed it is even harder when I let go off the gas and simply push the pedal to keep it in speed at around 1,500-1,750 rpms (awful feel right there). This is not that harsh in the mornings as the drive is not as long as in the afternoon. At this point, as the data does not show anything to support needing a new TC (I'm not looking to have it replaced but simply get the car fixed and have it behaving as a 1-year-old car) I'm simply at a standstill as GM doesn't approve the replacement because of the data, so tomorrow apparently I am supposed to pick it up the same way I dropped it off. Obviously to me this is not acceptable as I should not have to even think of taking a risk of doing another flush myself and with the limited time I have.

Can anyone help out here, especially from GM?

What TSB did the dealer perform on your car? Also diagnoses is NOT REQUIRED for the most recent TSB (18-NA-355) issued by GM. Take your car to a different dealer if that’s what they’re telling you.