I've owned my '89 300CE for about 6 months now. and have messed around with it unmercifully. It ran perfectly when I bot it, But I couldn"t resist, it now has about 160 k on it.
When I bot it it ran 3k RPM at 70 mph.
I've replaced/changed air filter, rear end gear oil, fuel filter, dist cap and rotor, spark plugs and wires, trans fluid and filter, changed to synth oil in engine...a bunch of stuff.
Now, I swear it runs about 2.8K RPM at 70 mph.
But this seems impossible to me. In top gear the crank turns the trannie which turns the rear end, etc. Everything is hooked up and locked in gear.
Could I possibly be saving RPMs? Saving MPG is understandable, but RPMs?
I think I'm just giddy with how smooth and quick it's running.

Maybe your Tach is on the brink

You may get better response in the "tech help" section.

__________________
Brandon



2008 S550
1957 Dodge D100
1967 VW Microbus 21 Window
2001 Suburban
2004 Beach cruiser bicycle
-----------------GO DUKE!-----------------

"It cannot be emphasized too strongly or too often that this great nation was founded not by religionists, but by Christians; not on religion, but on the Gospel of Jesus Christ. For that reason alone, people of other faiths have been afforded freedom of worship here." Patrick Henry 1776