91 W-150 4x4 318 Auto. Can anybody help me out there. This just started happening. Engine fires and idles great. Once I put it in gear it starts to miss randomly, just one or two misses then back to normal. But then on occasion the whole truck will shudder/jerk as if it was a manual and I did a bad job of letting the clutch out. It dosent die but sure close.

New cap/rotor, plugs newer and look clean, new fuel filter, vacuum lines look good, trans fluid still looks clean, good pcv,egr,map sensor checked out with multimeter, fuel into tbi looks good.

Any ideas?

 

have you checked the o2 sensor. it is responsible for you fuel to air ratio.

 

I installed a new O2 sensor and no difference.

 

have you tried doing the timing?