I just bought an 04 aveo 5 speed manual yesterday. I know next to nothing about cars so please bear with me. The check engine light is on. I went to have the codes checked today, I don't remember the exact codes but there were 5 of them. 3 were the same for crank Something. And the other 2 were evaporative emissions something small leak. I read about the gas cap being able to turn that light on if it's not tight enough which it wasn't and it's broken so I can contribute that to that and get a new one Anywho today I drove about 2 hours from where I live, highway speed limit 65 with lots of hills. The car accelerates just fine, engine is quiet and I get lots of speed and power, on flat roads. Start to go up the hill and begin losing speed, rpms go down steadily with the speed so I end up going 20 on a 65 mph highway and "flooring it" going nowhere. It feels like the car is cutting out like it's just going to shut off but it's mild and the car doesn't die. . once I get up the hill the car picks up speed again and drives like normal. Please help I love this car already haha any help would be greatly appreciated. I also have a mechanic fixing the crank whatever it is tomorrow and it's only a 50 dollar part if that helps anyone. Thanks