Under certain terrain and conditions, i have and do. Not the fastest way to get places, but not all that much slower. Search "absurd mileage".

 

Driving like a geezer (of which I are now one-I turned 65 today!) the best I have seen via DIC has been 31.7 on mostly highway while running 5 mph below posted speed limit and coasting downhill in neutral. Seems that keeping engine RPMs below 1900 is key. Now this is @161K with an old air filter, AC off and I do not know when or if the sparkplugs have ever been changed. That is about to be remedied along with various other neglected maintenance items. ,

 

Like a loose stretched timing chain? Or broken front guide! Dirty throttle body and MAF sensor