Surging Cruise Control on '85 300D
 

I noticed that every time I try to use the cruise control on my '85 300D it works fine for a very short while and then it starts surging by trying to keep the speed constant. It's too annoying to use like this at all. This is the only thing that keeps me from taking the car on any long trip. Any clues to the problem. Am I probably lucky that it even works this much?

http://www.peachparts.com/shopforum/search.php?action=showresults&searchid=569107&sortby=lastpost&sortorder=descending

lots of neat stuff about vacuum, actuators, c.c. amps...

Thanks! I probably should have done a search before posting my thread.

No worries, and you're welcome!

my 85 300d did the same thing, especially coming off a hill, it would pump the acc pedal up and down like crazy, surged and raised cane all the time.
be careful with your diagnoiss, its not always the amp. mine was the differential. the spider shaft had worn a huge slot in the carrier assembly causing excess slack in the drive line. replaced with a good used one of correct ratio, cruise works perfectly!!!! also noticed much smoother shifts for some reason???? i wonder why???????
good luck