I have the above vechicle with a straight six engine and with 100,000+ miles and have a problem that has been ongoing for sometime and am totally confused as to what to do. The pickup starts great in the morning and idles fine. No roughness during accelleration or anything while idling. I take my daughter to the bus stop and seems to be running fine. When I drop her off and drive for a short while the engine gives a bucking kind of sensation. This happens at the low end of the “Normal” range of the temperature guage and apparent when driving around 40 - 45 mph. I think that it may slightly be running a bit rough at freeway speeds but I cannot for sure tell (Idaho roads are not the smoothest. ha). When the engine gets warmer it doesn’t seem to be happening.
What could be causing this? I gave it a tune up before (OEM plugs, wires, rotor, cap) and it still happend. I made sure everything was even Motorcraft to see if that had anything to do with it! My nephew replaced the hoses at the top of the engine (I think they are return hoses) because they were bad but still having problems.
Any help is greatly appreciated!!