Today I swapped my intermitent cruise control unit on my 75 Grand Am for another one from a 74 Grand Am donor parts car and it worked like a charm, pushed the button at 65mph and it stayed rock steady all the way home on the TransCanada Hwy ... it should help saving a bit of gas, lol
Those old units have a habit of wearing out and then they surge. We used to sell rebuilt units at work but of course they are obsolete now. We got them rebuilt by a guy in Rathwell. His last name was Nostedt and he ran the hardware store. I don't think he does them any more but if you are around Rathwell, stop in at the hardware store and ask. You may be able to get your old one rebuilt.
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1966 Strato Chief 2 door, 427 4 speed, 45,000 original miles
1966 Grande Parisienne, 396 1 of 23 factory air cars (now converted to a "factory" 4 speed)