Might be the old return spring is a little stretched out/weak. I have the earlier style 22RE throttle linkage and I put on a stiffer return spring:

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I picked up the spring at the local hardware store, took the old one to the store and found one a little stiffer and about the same length. Has worked well, makes for a little more pedal pressure and that works well off road, where I don't get the surging throttle as you crest bumps making your foot push down on gas pedal.