NHTSA Complaint #11462501 — 2004 GMC YUKON XL

While driving on the freeway at 75 mph I felt significant reduction in speed and the rpms went pretty high. It felt as if I had my foot on the accelerator and the brake at the same time. There was also a burnt smell. After a few minutes it went back to normal. This continued to happen sporadically so I took it to my mechanic he inspected the vehicle could not find an issue he also ran a code scan. No codes pertaining to this issue only knocker sensor and O2 sensor. I replaced those anyway. Then a few days later I was driving to work at it happened again going about 55 mph it felt like the transmission had downshift to a very low gear there was smoke and really bad burning smell. I pulled over immediately and called my mechanic. He towed the vehicle to his shop still could not find a problem. After several months of sitting I had to drive the vehicle home. After approximately 5 miles there was smoke and small flames coming from behind the front drivers side wheel. My mechanic checked the brake, it had engaged without me pressing the pedal and stuck. Now we are having issues getting brake fluid to the rear brakes. Possibly the proportioning valve.