cruise control is very weak
Cruise control will hold at 65mph on fairly level ground but when a average incline is extended for about 2miles as on a long stretch of highway, it will slowly loose speed, about 8-10 mph untill the road flattens out again. You can feel the cruise control trying to work but is very weak. Is it the computer or maybe the vacume plunger or something else. How do I check it.
I would check the vacuum hose that feeds vacuum plunger. It could be the vacuum plunger itself, but the hoses are easier to check and replace. It could also be the length of the cable going to the throttle plate from the plunger. If it's too slack, it can't open the throttle enough to maintain speed.
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