Surging while using cruise control - vac leak?

[joemomma]

So I rarely use the CC in my car, but threw it on today on the highway. I've used it a couple of times before, and noticed each time that it didn't hold speed very well, or wanted to "surge" with cruise engaged. Would this point to a vacuum leak, or something else? I should note that my speedo is whack from the gears and needs a new gear installed at the end of the cable.

 

[Daryl]

Possibly. I was experiencing the same thing with my CC when I first got the car about a year ago. Unfortunately, my car has been out of commission for a while now.
But, back to your question: I did repair the vac lines that tie to the air selector knob. Worked fine after that. So, I’m thinking same for you might just be the answer!

 

[joemomma]

Forgot to update this: I replaced the speed sensor, and that helped quite a bit. My vac lines are probably in bad shape, I should go through and repair/replace the majority of them and clean up what I can since I removed the smog pump.