A mechanic put a used one in, which worked about a year. I put in another used one and it started surging after 30 days on hills. The vacuum lines were replaced.

What would you try next? Someone told me these things rarely fail. Thanks. Bob

 

It really sounds like you have a vacuum leak, regardless of whether the lines were replaced, I would check and double check that.

 

Are they big long hills or just really short ones? If there big long ones your not suposed to use crusie control on them because you'll get what your describing.

 

and it also will do that to keep the speed up and will shift in the gear above (from 2nd to 1st) so it will make it easer for the engine to hold it at the speed

 

Sometimes it shifts gears and then backs off again. Most of my driving has been in Illinois. Short hills going up a hundred yards or so will do it. In other words, the cruise worked ok on the same hills than something went haywire.

How do I check for vacuum leaks. Soap suds? I replaced the plastic ball with a used one once.