1990 D-150 runs rough

1990 D-150 S, 318 TBI automatic. Everything original to truck is still in place.

Last week, my Truck started missing and jerking while driving to work. I got there popped the hood, and couldn't see anything out of normal since it was dark. Before I shut the hood I seen a spark jump where the wire mounts to coil.

Thought ok, in morning I'll pull the wire and make sure its snug befor going home. Did that and it ran like a champ.

Next day same thing happened, no sparks jumping around anywhere this time, so I figured probably time for new plugs wires cap and rotor.

Did all of that and runs fine until it gets warm and starts missing and jerking while driving and now a noticeable miss when warmed up.

Thought what the heck, scan tool is showing no codes other than 024 which is a cruise control servo code. Truck doesn't have cruise.

So I put a new fuel filter on it and a new coil. Runs perfect, until it gets warm and starts falling on it's face again.

I have scheduled an appointment with a local repair shop next week, but would like to figure it out myself before eating a big repair bill.

Any advice from the experts??

Thanks

Gary
Author: gwgdog66