i have an 87 f250 with the 4.9 manual in it and I am gettin about 10mpg! what the hell is going on, i just dont get it its a 4x4 but im not just wide open all the time, well actually never.... what is wrong with my truck? ANY ADVICE would be awesome

 

Does the engine seem to be lagging. I would check e-brake to start with, check brakes see if there dragging. Is the timing right? Plugs gapped correctly, correct firing sequence. Check those things first, also run a bottle of fuel system cleaner through the tank see if that helps.

Later,
Don

 

Also when was the last time you had a tune up? Air, fuel, pcv, plugs, wires, cap, rotor? Are you towing alot, hauling alot? I got 10mpg with my 36's and a 351w.