I have began to notice after driveing for 20 mins or so my 4 runner starts losing power. Last Friday on my way home from work going down the interstate I keep having to give it more gas to keep the speed up. After sitting for about 2 hours it was better still kinda week but again after about 15 mins it started getting really bad again. Any ideas ?

 

Run a compression test, cold, wet and hot.

 

problem found it was the cat was clogged up there was a small opening and when it would get hot it would close off. New cat and problem is all gone.