I have an '89 E-350 with FI 460. The engine was recently replaced with remanufactured but compared to the old engine (which had badly burned valves) power is significantly less and gas mileage dropped from an average of 12mpg to only 6mpg with the same driver and general (easy) driving conditions.


It starts and runs okay but I'm suspecting the cam is retarded. I put a manifold vacuum gauge on it and with idle ignition timing at 30deg. the idle vacuum sits at 16" Hg. Anyone with 460 experience care to speculate?

 

If you don't get too many replies here FTE does have another sub-forum dedication to that CID and era engine: Big Block V8 - 385 Series (6.1/370, 7.0/429, 7.5/460) - Ford Truck Enthusiasts Forums

HTH