So I'm motoring along a country road with the cruise set at 50 mph and the truck starts to increase speed.

Tap the brake - nothing happens. I'm up to 65 mph!

Knock it into neutral and it revs to around 3,500 rpms and then it unsticks.

What in the world is going on with that?

After thinking on it, a few miles farther on and I set the cruise again.

It began immediately picking up speed. I hit the brake and nothing happened. Then I hit the off button and nothing happened.

So again I bumped it up into neutral and it did the same thing - revved for a moment and then kicked off.

The dealership where I get my service done can't get to it for several days. So I'm checking in the meanwhile to see what suggestions you have to identify a cause.

Thanks in advance!

 

I've had my 99 Ranger randomly do this several times, but some time ago. Since replacing the IAC & rear differential speed sensor with BWD brand parts 5 years ago to remedy other problems, it hasn't happened again. I too had to bump the shifter into N & let the engine wind up until the rev limiter kicked in & stopped it.

 

EDIT: I couldn't see that you have a '10 Ranger til now because signatures don't display on the mobile site. I have no idea if those use a separate cruise module or if it's done by the electronic throttle body or what, so the below info assumes your truck still uses a mechanical throttle body and separate cruise module.


The cruise module not responding to the OFF button and brake switch would lead me to look at what is common to those two inputs. They may or may not also have one or more things in common with the speed signal input.

The reason I mention check speed signal input is because if the module was losing it's speed input, that is the only reason for it under normal operation to increase throttle.

​​​​​If you find nothing in common except the cruise module itself, then I would replace it.
​​​​​

 

Thanks to both of you for the feedback. I'll start running down the potential culprits on Saturday.

 

Ok, here is a link to wiring diagrams that might be helpful. Search Wiring Diagrams
Also if you have, or can come by the inexpensive ELM scan tool, running FORScan, or the like software on the viewing device of your choice, like discussed here, https://www.ford-trucks.com/forums/1...-scantool.html it can scan All of the vehicle computer/controllers, including the GEM, for an in depth look for trouble code clues that could help focus your trouble shoot.
Let us know what you find.