My dad truck has some serious misfires.. its a 98 f-150 4.6. It all started when the heatercore went out, from there it started to misfire. so, I though it might of been plugs and wires, because it has 100,000 miles on them. changes them still having the same problem. Took it to a shop .. they said something about a ignition switch, changed that still having problems. I recently got my buddy obd2 scanner . it said lean band 2 and egr ... something... hooked a manual vaccume pump up to it... still opening and closing. its driving my dad crazy.. and its his daily driver. I ahve no idea what the hell it is. My buddy has autotap, but hes in college now, so that doesnt help much.

anything would help thanks.

 

Try pulling the harness away from the a/c accumulator tank near the firewall. This solved a similar problem several years ago that we first thought was unique to 5.4L engines, but ended up affecting a wide range of Ford trucks.

Info

 

grr did work ,, im thinking a dead coil...

 

It did work or it didn't work? If it did work, keep the harness away from the tank.

 

heh ..,.. didNT work my fault.....