Has the oil and filter been changed recently?
Has the tranny fluid been changed?
How is the air filter?
Did you check timing belt condition and tension?
Is the cold start lever position to run when you posh the plunger in?
Are you using a tier 1 vs tier 3 rot gut diesel fuel?
Have you checked the parking brake tension?
Have you checked the rear wheel bearings?
Is the clutch petal adjusted properly?
Try going 55mph, but I bet the above wil leasily get you over 60mpg.
