So today around 5:30-6 i checked my oil, it was fine, maybe a tad full, and then about 30 minutes later my mom got in the car and tried to drive it (shes not too good at stick) and revved it to about 6k (fairly warm). The heat was blowing hot so the engine was probably warm enough, but then the ride got kinda chuggy, as though we were on a dirt road. When we got home we looked and there was quite a bit of smoke that came out of the tailpipe, and smelled like the inside of an engine-swapped car. Its very cold here, about 20 degrees fahrenheit. Its been sitting for a while, 4 years-ish, so could it just be bad valve seals and old gas? Or is it the dreaded BHG?