I read that here and was happy that I had a W124, getting 33 mpg combined on B100. Then it pooched the motor due to a vaccum pump fiasco. Replaced it with a W210. Now its at 28-ish.

Why? I should check the registrations, maybe the W210 is heavier? Assume with some chip control in the 97 it would be better? Sure teh 95 mill has loose, but assume better sealing in the 97 would offset tighter internal clearances.?

Have done the usual filter changes. Did pick up 1 mpg with an air filter change.

Lastly, has anyone messed with a custom chip in their 97? Can anyone recommend a company?

Can they defeat the EGR using electronics?

THNX!