When I set the cruise control about a third of the time it doesn't engage, another third it works fine and then the other third it makes the car go to WOT. I let it go once just to see what it would do and it went to 100mph as though it were set for that speed. I just turn it off if it does number one or three now, but andy idea what its problem is?

 

i have the same problem with mine....without the WOT part. some times when i set it it works and other time it doesn't. sry i don't know the answer, so i guess this is a, TTT+me wanting to know the answer too, post.

 

Check your vacuum lines coming out of the cruise control unit. Make sure the lines are in good shape and not cracked. Follow the lines back and make sure the are still connected to their vacuum source. Whick should be either the manifold or maybe even the trottle body. It might depend on what kind of car you have.

It is also a possibility that the diaphram in the cruise control unit is cracked. Might be worth checking out.

 

Dont forget about the elecrical side of the equation. You could have a bad switch or a bad control valve.