2003 Chevy Malibu hesitates on hills

I lose power going up hills and accelerating, but I am getting 29mpg out of the 3.1 malibu. After a 30min drive it smells really hot mostly around the fuse box area in general. Turn signals stop working sometimes. Checked the egr with a 9v and was working properly, Cat and O2 sensors are new, Coil packs new, plug wires and plugs have about 15,000 miles on them, intake gaskets replaced, throttle body cleaned, MAF cleaned with MAF cleaner, throttle position sensor new, thermostat about 15,000miles, was overheating before replacing cat. Oh and I replaced the trans filter, no flush from dealer. I am banging my head when I hit a hill. I need to forget about it, but I don't have anymore money to put towards this. Any testing I could do to check MAF or any other sensor.