About once in every four or five times when I turn the cruise on (92 Formula L98), it takes off like a banshee and accelerates. Now, it makes a really cool sound when it does that, but I don't think it's supposed to. Lol. Other times it works normally, meaning, the revs go up for an instant, then right back down and it settles in. I know most cars rev slightly when the cruise engages, but this is more dramatic. It just keeps going and takes off. Sounds like an electronic issue because it's hit or miss whether it will do it. I'll attach a picture of my engine. It has the vacuum pump, but I think there's an electronic component as well. Bad solenoid maybe? I haven't worked much with cruise to know a lot about it. Or a vacuum line issue?

 

You can see the cruise apparatus here.

 

would you like to get a known good working unit to replace it with? i just pulled my entire cruise system out since 1. dont like cruise 2. dont use cruise.

 

First check would be vacuum leaks. Lots of brittle hoses running between engine/orb/servo, and if I recall, there might also be a vacuum break on the brake switch (can't remember).

Here is the wiring diagram, might also be worth the time to ensure all the wires are intact.

 

Ok, thanks. One thing I've noticed is that it tends to do it more if I'm pressing a little on the accelerator. If I let off just a bit a split second before I hit the button I don't think it does it.

 

Does this happen when you hit the Set/Coast switch or the Resume/Accel switch? I've seen the Resume/Accel switch stick on some vehicles.

 

Let's see....I flip the toggle switch on the front of the lever to the on position, then tap the button on the end of the lever to activate. I'm not sure what the name is for each switch. I think the toggle is the resume/accel and the one on the end is the set/coast right?

 

That's right. The end is your Set/Coast. If it got stuck, it just wouldn't work. The 3 position slider switch is Off, On, Resume/Accel. If it got stuck, it would Accelerate. So basically, if you had already Set a Cruise speed, had to put your foot on the brake to disengage it, then tapped the Resume/Accel to resume to your previously set speed, but it got stuck in that position, it would continue to Accelerate, though it should immediately disengage with Brake apply.