RE: Cruise Control Problem
Service manual asks to check following things:
2:Check operation of brake lights cause voltage from light switch deactivates cruise.
If brake lights stay on all the time or don't come on at all repair the brake lights circuit.
3:Check the control cable between cruise control servo and the throttle linkage for free movement
4:Cruise control system uses inputs from vehicle speed sensor,check sensor.
Point that you don't get any fault codes actually should mean that speed sensor is working and
connector I mentioned should be ok.(I got code 34 when connector was not connected)
Electrical fault would be possible,those occasional faults coming and going seem to be the case with 1gen body.
But again you don't have codes.
How about vacuum pipe coming to servo,have you checked it.
Without any codes from the list in the beginning we have only points 2 and 3 left,and that problem with vacuum.
According to manual if all things on the list are ok car should be taken to dealer for checking cause
further investigation means need for special testers.
I hope you find the reason for malfunction.