I have a 1986 f150 5.0 it idles fine but when I take off and it shifts gears it shudders especially when it hits overdrive changed plugs wires rotor and cap can someone please help me out
Have you checked your tranny fluid,may be low,and check your fuel filter all so.
I have nothing but Fords my adult life and have seen this problem numerous times. It starts out as a shutter when going into OD. If you take it out of OD it stops. Basically when you get the RPMs up it stops. Everytime time I've had this problem it turned out to be a cracked vacuum line. I'm actually having the problem now with my '05 F150 but haven't found the vacuum line causing the problem.
Have you checked the vacuum to the modulator valve, or the valve its self on the transmission? Just a thought
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