Trouble with the Throttle

So, I just posted about an issue with my 2000 Jeep Cherokee 4.0L starting. Now it’s been starting just fine, but unfortunately a previous throttle issue has arisen. Here’s what happened:

I was driving along the interstate, when all of the sudden, at 55 MPH, the throttle stuck–the car started accelerating without control, and pressing the break did nothing. Eventually we managed to gradually slow down the car to about 30 MPH with the emergency brake. We couldn’t get the car any slower, so we moved to the side of the road and put it into park, just to turn it off. (By the way, I realize that what we should have done was move the car into neutral and let the engine turn off as the car slowed down. But when you’re on the interstate with no control over your acceleration, it’s hard to think of that first.)

Anyway, we managed to get the car to a nearby shop, and the guy put some carb cleaner and penetrating oil on the throttle body. It seemed to work, but the fact is, I’ve had similar issues with the throttle before, and I wonder what else could be causing this issue than a simple dirty throttle body. Has anyone encountered anything similar with a Jeep? And could there be any other reason that the throttle consistently gets dirty?

Oh, and to top it off, the breaks are shot because of our slowing down. Hooray!

Boy! You’re battin’ a thousand aren’t ya? You make it seem like my wife’s old Cherokee came home to roost.

The throttle body linkage on this engine is probably the worst design anyone could come up with. The linkage mechanism is attached to the intake manifold. And over time the linkage/springs rust and the throttle can stick.

When the wife had her Jeep, the throttle stuck for this reason. So everytime the oil was changed the throttle linkage got a good application of Seafoam Deep Creep to prevent it from occuring again.

Tester