w124 Cruise control "revs"...where to look first
 

This is on my 1987 260E.
I did a long trip from Orange County, CA to Tempe, AZ over the weekend. 380mi each way...drove beautiful. Only issue was Cruise Control not working properly.

Basically it engages, but it "revs" and I can see the economy gauge go left to right slightly at a very fast pace. It is jerky, but functional. I did not use it for fuel economy reasons, but wish I could have.

Anybody know what could be the issue?

Thanks,

My '87 300E did sort of the same thing. On flat or up hill grades it was fine but when I headed down hill it would lurch. I could see the tach and the Economy gauge move when it was doing this.

Did you ever figure it out?

Could it be the module for it? (Is the name the CC amplifier?)

I didn't figure anything out. It just happened yesterday. I'm going to look into it though. I'll let you know what I find.