mmissing aerostar

! have a 86 ford arostar. Ugly but runs great, until last week while heading home, doing 65 mph down the hiway when it started to run rough. I replaced wires, cap, rotor, front four spark plugs. lookig for cheap fix. Any help?

fuel filter?

I've got an 86 too... do you have the 2.8 or 3.0? They also had the 2.3 I think...

2.3l FI 140 CID VIN A O.H.C.- SOHC,

2.8l 2BBL 171 CID VIN S O.H.V,

3.0l FI 182 CID VIN U O.H.V. which one do you have??

Try changing the last 2 spark plugs, if that doesnt work then unsnap all 6 sparkplug wires from the plugs but let them still touch and start the van. One by one with a set of plastic pliers pull off each plug wire until all 6 are done. You are listening for a change each time. If it doesnt change then you have a bad wire, or posibly a bad plug, or cap. And yes I have done this before, I never said it was going to be easy. Those back 2 plugs are hard to get to. Good luck!