I am always trying to squeeze some more diesel out of my old 1984 Mercury Lynx diesel 5-speed (211k). I consistently get 50 mpg on my daily commute of 30 miles round-trip. Lately, I've reduced the weight as much as I know how (removed spare tire which was dry rotted anyway + removed back seat) and increased the tire pressure to the tires' max cold of 35 psi.
My next goal is to locate light-weight alloy wheels to replace my heavy original steel wheels and install low rolling resistance tires. However, I have found that locating alloy wheels that fit is a problem.
My father had the good sense to buy the car new in 1984 and I bought it from him in 1990. I call it "The Little Gray Ghost" as it has risen from the dead several times after serious repairs to the frame and body due to corrosion that got out of hand before I discovered it. However, no problems ever with the engine and drivetrain.
If anyone has one of these rare little diesels I would like to hear from you.