Macrobb
Full Access Member
I'll bet your timing is slightly off(probably retarded). The higher in the revs, the less time to burn the fuel, and the more timing advance needed.I have not collected information to substantiate this however, it seems fuel efficiency is far worse when RPM's exceed 2000 to 2200. Beyond this, mines seems to drink fuel. Some of these highways with 70mph speed limit and traffic flowing at 80mph, if I run with the crowd, you can almost watch the tank empty.
With a worn pump which doesn't advance as well as it should, you can end up with retarded timing up high, which, of course results in higher EGTs and less power made from the same fuel = more fuel needed to maintain the same load.