Q&A

It sounds like an engine misfire to me. The most extreme load on the ignition system is in overdrive at 45-50 mph - the torque converter clutch may also be applied at that time. This solid lock-up of the drive train makes the feel of the misfire more severe. All of the secondary ignition components (plugs, wires, ignition coils, distributor cap and rotor - as equipped) will need to be inspected and replaced as necessary.

I have the same issue ...even tried to put limited slip additive in rear end... your description is exactly what my same year truck does. 2003 F-150 extended cab 4X4

YOUR CLUTCH PACKS ARE WORN OUT IN THE REAR END THEY ARE LIKE BRAKE SHOES IF YOU WILL CONSIDER TRY A SMALL BIT OF POWER BRAKE AT A STOP AND MAKE A MODERATE TURN AS YOU LET OFF BRAKE CONSIDERING YOU CAN FIND A CLEAR ROAD YOU DO NOT HAVE TO PUT TO MUCH IN TO IT TO SEE IF THEY ARE FAILING BUT THE DIFF PLATE WILL HAVE BE REMOVED TO INSPECT GOOD LUCK bing

I had a 87 F150 do the same thing , it was a 5.0 , and I found the fuel pressure @ 80lbs. @ the fuel rail , it needed a fuel pressure regulator , however you have to to a fuel pressure test to find this to be true or not , also Fords are known for the Stator in the distributor to short out causing low ohms , which would cause a miss fire or the lack of fire during acceleration , either way there's no quick fix it must be diagnosed by someone with good knowledge of how the Ford system works , hope this helps , Kevvs

If you hook it up to a computer, it may or may not read out, but in mine it was a coil/sparkplu issue that was screwing up my timing. Replaced the plug, boot and coil. easy cheesy.