It's a 4-cyl. In all the years I've owned it, nothing has gone wrong until now. Found that when it's cold outside and the car has not warmed up yet, the cruise control is not stable when set in 2nd gear. The vehicle speed may vary + OR - several MPH...rapidly! Recently, I saw similar things happen in 3rd and 4th gear. When the car warms up, the problem seems to disappear. The vacuum actuator solenoids check out OK. Doesn't seem to be any binding in the cable. All the switches seem to work. I've noticed that things seem better when the main switch is turned off and on again. I'm thinking that maybe the contact in the main switch is corroded and dropping voltage. If the CCU draws an ampere, and the switch is at 3 ohms, the voltage at the CCU power input will be only 9 volts.....not 12. Does anyone know their CCU modules? Would that cause the lack of stability? Anyone seen this happen? Unfortunately, it's not cold here at the moment so I can't confirm anything....I will post the solution when it's solved.

 

Well, I bought a new vacuum actuator, new cable, and new vacuum tank. One afternoon I took it all apart and ran the tests they have in the service manual. One of the tests on the actuator "flunked". A solenoid valve was stuck "open". Repeated the test several times....no change. Put it all back together, with the new vacuum actuator, and all seems well. Although there has not been much in the way of cold weather of late. Returned the (unopened) parts I didn't use and got a refund on them. END-OF-PROBLEM.

 

I've actually never tried using control when the car is cold I believe, but it may be normal. I think cruise control doesn't work until the car is warmed up.