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Q: Engine pulls/bucks at highway speeds

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Last week my car started pulling on the highway around 60mph 2500ish rpms. I thought it was the vaccum advance and swapped it out. It was leaking so I thought the issue was found and solved but now it does the exact same thing around 50mph 2000ish rpm. I have better vaccum pressure now but i don't know what it could be.

My car has 56000 miles.
My car has an automatic transmission.

It sounds like you have a lean misfire or an ignition misfire. I would start by checking to see if the coil is putting out a large hot spark. Then replace the points and condenser as necessary. If the problem is still happening once these are done, lightly spray the ignition wires with water at night to see if the wires are arching. Replace cap, rotor, and wires if they are, along with a new spark plug set. Check to make sure carburetor is clean and tuned.

I’d suggest you get the vehicle looked at by a qualified technician who can diagnose your harsh driving symptoms firsthand. They will be able to perform the checks that I’ve mentioned and make any repairs that are necessary to get your car running normally again.

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