Trouble with a high millage 5.8

[94wind351]

I have had my 1994 250 5.8 for 12 years and have never had any trouble with it that I couldn't figure out on my own. It has recently decided not to run real well. It will run great and with no notice start to crawl and eventually stall. I have replaced the plugs, wires, cap, rotor, distributor, ignition control module, ignition coil and fuel filter it runs better now and I haven't had it stall in awhile however I haven't driven very far distance do to a newly found trust issue with my truck it still spudders out a little bit at idle and low RPM any ideas? could the timing be off just enough to cause the rough idle? seems I can turn the distributor enough to either have a good idle in park or neutral or In drive and reverse can't seem to find the medium. Please help.