i have a 97 4runner, automatic transmission and once the car hits about 50 mph it starts jerking when you try to accelerate anymore or hold a constant speed. the only way to keep the jerking to a minimum is to hold high rpms. there seems to be decreasing power too. any ideas? (there is an upgraded k&n air filter for it and it is a limited edition 4runner. it's not a knock either, it feels kind of like it's trying to shift or it's running out of gas)

 

Sounds like a air/fuel problem, does the check engine light come on?

 

no check engine light. i did some research and ended up cleaning the maf sensor but didn't have any luck with it. could still be dirty.