Periodically while running at high speeds (70-80) the rpm's will jump up to 4,000-6,000 as though you put the pedal to the floor to accelerate. This can happen both when on cruise control or without. It is very sporadic. Initially it was disguising itself as a Mass Air Flow (MAF) sensor problem because I would get a check engine light and the fault code was the MAF. I continued to have this fault until I replaced the aftermarket MAF with an OEM and the fault has stopped except that the rpm's still sporadically jumps up except I get no check engine light or fault. This has never happened at lower speeds and only sporadically at higher speeds. I just talked with a transmission mechanic and here has never heard of this issue. I was thinking of having the fluid and filters replaced in the transmission. The vehicle has 133K miles. Has anyone else had this issue or heard of it??