My truck has the 4.3 vortec engine and has 307,000 miles on it and the transmission. It has started "bucking", or jerking, especially between 40-50 mph when it is allowed to decelerate. I've also begun noticing it at around 30 mph. It almost feels like either a miss or like the transmission is acting up.
Feb 5, 2013 at 1:46 PM