I have a 88, 4.9L, manual trans., F-150 with 60,000 miles on it that misfires in between the 2000 - 3000 RPM range. It runs better when cold. Usually misfires when accelerating. Cruises well on the highway. Or at least I can't feel it when on the highway. I've brought it to two mechanics one of which was a Ford dealer. This is what has been replaced so far. Almost the whole ignition system (plugs, wires, cap, rotor, distributer, ignition coil & ignition module). EGR valve & ESR selenoid. All six fuel injectors and fuel filter. The oxygen sensor and few other things I forget without looking at all the receipts. One mechanic tried blocking off the new EGR valve, it got a little better but lost a lot of power. Ford told me it was the fuel injectors but that didn't help. Anyone else have any ideas. I'm about ready to bring it to different Ford dealer and let them give a stab at it. I've sunk well over $2000 trying to fix this problem.