Hello guys my name is Steve and i am new to the forum. I have a problem you guys might be able to help me with. I have a 94 Mazda Navajo 4x4 with a 4.0 an d last nite i was driving when the engine revved up to 5000 rpm and would not back off i shut off the engine and re started it it was ok for a few minutes and did it again. After i got it home i waited untill today tried it again today same thing. Has anyone else had this problem Any help would greatly be appreciated Thanks in advance for your help.

 

Check the throttle cable to make sure it isnt sticking

 

Yes, check throttle cable and Cruise control cable if so equipped.

Open and close them manually and see if they stick and make sure throttle return spring is not broken, this spring needs to be tight to close throttle and block air flow.

Other thing to check is the IAC(idle air control) valve.
It is located on the upper intake near the throttle.
This is a valve the computer uses to set the idle level, computer opens it a bit to increase idle and then closes it to decrease idle.
Not sure it could raise it to 5,000 even if opened all the way