You must clean and lube the throttle linkage. It is one of the periodic maintenance items. Lubing a faulty linkage won't make it worse as often as the over looked promlem will.
Dirty linkage is the first item to rule out. It helped my periodic down hill problem for a short time, but finally became jerky down every hill.
I had a very bad flex disk, but repair had no effect on frequency of jerks.
Rebuilt control fixed the problem. I believe the MB fix of re soldering the circuit board will fix most controls, if one has the skill and patience to do so. Or $$ to replace, as I did.
They that can give up essential liberty to obtain a little temporary safety deserve neither liberty nor safety. Benjamin Franklin, A.D. 1759