Cruise control won't hold speed.. What to check?

[mysocal911]

Originally Posted by uwanna

86-89Carreras use exactly the same system with vacuum servo and module, with two exceptions. They use a 14pin module vs 10 pin, and the module is relocated inside the car under the dash. It operates identically.

Correction: '88-'89 Carreras started using an electrical servo in lieu of the vacuum servo. Basic operation remained the same.

Actually, that's not totally correct. The late CC ECU ('88-'89) is a digital system where the set speed
(a digital count) is stored in a register. The older CC (10 pin) system is an analog system where
the set speed is stored as a voltage on a capacitor. The later system is much more stable, accurate,
and reliable.

[GH85Carrera]

Originally Posted by kyngfish

The way I like to fix the cruise control is, check and see if it's connected. If it is. Disconnect it.

No idea why these cars have cruise control.

You obviously never done a long cross country drive. Try going 900 miles in one day. I have done that several times and cruise is a great thing. Oklahoma City west on I-40 for 900 miles is Flagstaff, AZ. OKC on I-40 east for 900 miles is Maryville, TN. I have done both of those twice.

On the track or the curvy roads it is as useless as the back seats.

[Uwon]

+1. I have 379,000 km on my second speedometer. No garage queen! Long distance touring, daily driver, track. The CC has extended my enjoyment of the car.
Johan