Is there a way to lubricate the accelerator cable on W124?
 

If I press my accelerator to the floor (trying to get up a hill or something) it's a bit slow to come back up which is scary. There's about a 1 second delay. I'm assuming the original grease from 1991 has hardened and become like peanut butter.

Is there some feasible way to lubricate the accelerator cable? (not the speedometer cable. I put that in originally but can't edit it)

Yes it is easy to lubricate. Pull the instrument cluster, unscrew the cable from the speedo, pull out the inner cable paying attention to which end goes to the cluster and clean the hardened grease off to it. Spray it with Würth HHS-K which is a great grease that is in a light carrier. After reinstalling the cable, spray plenty down the cable and you’ll be golden.

Throttle or speedometer???

If you’re actually talking throttle, first remove the cruise control linkage. For whatever reason, cruise gets stiff, and can cause lingering rpm’s, if not big overshoots/over speeds for a short time as springs are bringing things back.

If the linkage balls are gummy/un-lubricated, that can affect things too.