My 1992 Lexus sc400 started revving by itself about a week ago, it revs to about 1700 then drops to 1200 and keeps doing over and over. I also noticed when I'm driving it, it starts to pick up speed with out me pressing the accelerator. When I'm at 45 mph it feels likes it's on cruise control. When I pressed my cruise control button the light in the cluster didn't come on.
I've tried cleaning the IAC valve checked all the spark plugs and wires, cleaned my EGR valve and a new MAF sensor. There are no vacuum leaks, I checked every spot with carb cleaner and I'm completely out of ideas... Any suggestions!? I would appreciate it!
Oh and do I need to do anything special for a new mass air flow sensor since it's an OBD1 or should it just plug in and work?