RockmanZ3R0

Hey, I recently noticed a re-appearance of a jerking at highway speed. It only happens at 54, 55, and 56mph, RPM remains stationary at around 1400ish and does not change when the car jerks.. When I am on the highway and accelerated up to any of these speeds, the car lurches/jerks once or twice, if I let off the throttle and slow down to the speeds it does it again until slower than 52mph. I had this problem when I first bought the car but after an oil change and air filter replacement, it seemed to just vanish. That was 3-4yrs ago. I recently had my battery replaced and noticed it's back again. Any ideas as to what is wrong? last time I looked at the sparks they were good, I know the bushings/control arm needs replacing but I fail to see why that would cause it to jerk ONLY at the mentioned speeds.
The other thing I <i>think</i> I noticed is, its only after the engine has warmed up, been driving around all day. The oil might be a bit down but I did a change (some 2000 miles ago) and it does'nt burn oil that fast. Engine itself has 130,000ish miles on it, car has 145,000ish
Its probably nothing, I feel stupid for rashly posting this question without first seeing more of when and what triggers it if it keeps on