NHTSA Complaint #11659468 — 2016 CHEVROLET MALIBU

Took my car to Chevy dealership to diagnose my car, as it was rough idling, causing hesitation, and knocking... all while the check engine light was on. They showed me two codes my car was giving from the check engine light. They said he would look further into it. They told me I needed a tune up, though I had gotten a tune up 4 months prior. They fixed some things and charged me over $4,000. The day I drove off the lot, the problems were still present. On my way home going about 50 mph, my car slowed down and the engine reduced power illuminated. I kept driving because I needed a car for work. The car continued to decline and acted like it didn't want to accelerate when pressing the gas. I finally took it back into chevy, and they told me it was my pistons. I'm 90% sure there is a defect that they won't tell me about, or the won't fix. I've had the car 2 years. Now the car won't run.