Gas Mileage?
 

I am getting 20mpg on my '88 300CE with 145,000 miles on it. Mostly highway driving with a light foot. Is this good or bad?

That's decent for a car the size of the W124 and the old fuel injection system. Typical W201s get slightly better, in the low to mid 20's. For better MPG, I would suggest keeping an eye on tire pressures, like twice a month, and keep up with regular oil and filter (air filter too!) changes.

In my 91 300E I consistently get 19 to 20 mpg around town and 26 on the highway using 87 octane. Your car is lighter - I would think it could do better...

Oh yeah, and that's with the A/C on all the time - I never turn it off, even in winter (though the compressor probably doesn't kick in during winter). My driving style is moderate to occasionally agressive. I have almost 135,000 on the car.

1989 300ce between 19.5 and 20 in mixed driving....about 23 on the road...

fairly light foot... mid grade gas...

btw.... the 1989 300ce weighs about 60 pounds more than the 1989 300e......