1996 Grand Cherokee Accelerates!!!!!!

[48473]

I have a 1996 Grand Cherokee that drives and rides great. The problem is that on occasion it will start to accelerate. Doesn't seem to matter if the cruise is on or not the engine will just start to idle up. I have had it to a number of mechanics and it still does it. I have replaced the throttle position sensor and I wonder if it could possible be the Mass air flow sensor. I purchased the vehicle from a repo lot and it has lots of miles. My intentions are to put a lift kit etc. on it just to have something to tinker with. Any help would be greatly appreciated.