Dad passed away last September, the last surviving member of his fighting unit from WW II. A few weeks ago, I flew from Detroit to Dallas to settle some family estate business. My brother gave me their 1997 E320, and it had been driven very little in the last couple of years of his life - short trips to the grocery store or doctor's appointments..... 69K on the odometer.
Not very often anyone just gives you a Benz....
I cleaned her up a bit, filled her up with Mobil 1, got some Lucas fuel injector cleaner, and filled her up with premium unleaded.
First tank : 21.5 MPG, but that included two hours in snarled rush hour traffic (won't do THAT again if I can help it).
Second tank : 24.5 MPG through the hills of Arkansas and Kentucky. I passed a couple of tractor/trailers at 95+ MPH - she still had plenty of spunk and was running well.
Third tank : 27.5 MPG for the home stretch. The old E320 had found her legs again, and was running like the proverbial sewing machine.
I haven't yet filled the tank again, but I suspect my mileage will be between 27-28 MPG. She's been driven a bit on some errands around town, and seems to be running very well.....she just needed to stretch her legs.
A new set of Michelins may contribute slightly to that gain, but I suspect the Lucas product helped a great deal. Not scientific, just my opinion. YMMV.