I have a 1991 Chevy Astro Van CL with a 4.3, rear wheel drive, A/C, Cruise, automatic transmission, 140,000 miles and ABS. My problem is my cruise control, when engaged it will hold at the set speed then slowly start slowing down to a slower speed.
If you push on the gas it will go back to the set speed, so it is still engaged but will do the same thing again. Sometimes it will hold for 20 miles other times not, especially on hills it is not effective at all.
Sounds like a vacuum leak as there is a Vacuum tank and lots of vacuum lines for this system. The actualtor also is a little vacuum operated unit which connects to the gas pedal its self - It may be that failing also. Good Luck
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