94 explorer auto trans shifting issues

my 94 explorer auto trans, all of a sudden, doesn't like to use any gear except 1st and reverse. it shifts into gear fine, goes off from start fine. but when it's time to go into 2nd, nothing happens, it stays in 1st. if i coast it, it'll go into 2nd, but when i step on the gas, it downshifts. any ideas? powertrain control module? throttle position sensor? trans governor? trans fluid level is high and looks clean. also, my engine rough idles only upon startup. there's a plasticy burning smell, and my fuel economy went down. could be all related?

could be MAF sensor causing fuel problems. Don't know on the tranny though, could be a clutch problem.

m f