With 500 miles on the Impala, one day just wouldn't turn over when trying to start, but had batter power. Turned key to off and tried to restart, this time success, but immediately noticed a problem. The engine ran as if not all cylinders were firing and vibrated heavily with a flashing check engine light. Turned car off and then back on to have it run normally with engine light solid. Immediately called Onstar to run diagnostics and they found a misfire code.

Now 4 months later and 5500 miles, it continues to act up at stop lights with RPM dropping to 500 and heavily vibrating as if a misfire, hesitation & sputtering when going up hills, hesitation when slowly increasing speed. In addition if you keep in park and rev to 1.5rpm it vibrates heavily. Dealership was able to reproduce these issues, however, GM is providing no fix.

Finally, the dealership brought 2 more LT2 Imapalas over to compare and they did the same thing. Again, GM has no fix or even has the slightest clue to the problem. They will not let the dealership start throwing parts at it as GM claims that it is "Normal" operation for the 2015 Impala V6.

While being in a loaner vehicle for a while, I am very angry with GM, not the dealership. How can they not have a solution or even offer to refund my money or put me into something else similar in price!