Hi, I have a Buick with about 140,000 and I have been noticing a slight “jerk” like someone is tapping slightly on the brakes while the cruise control is engaged.
This only happens for a few seconds and there seems to be no regular pattern to it. I very seldom notice it without the cruise on. My local non-Buick mechanic is recommending a tune-up.
His rationale is that the cylinders are missing and it is more noticeable in low RPMs and constant speed i.e. cruise. Today on the freeway with the cruise set at 76 and about 2200 RPM I did not notice it. Do you
think he is correct, or do you think it may be the transmission as I fear?
Tyler
Hi Tyler,
I think I would replace the spark plugs and spark plug WIRES first and see what happens. Worn our/bad spark plug wires can cause problems like this and it is a pretty inexpensive place to start.
If you still have problems after replacing the spark plug wires, I would take it to an automatic transmission shop and have them take a test drive with you and get their opinion.
Do NOT “flush” the transmission or use any transmission fluid additives without talking to the transmission shop first. You can make things WORSE!
Austin Davis