Just returned from a 1400 mile road trip, 1/2 with 12k load. Halfway thru first leg, about 4 miles after a fillup, truck started bucking like a PO'd bull! All guages indicated no trouble, so continued on. I blamed bad fuel for the trouble. Bucking stopped in about 5 miles, but had a continuous misfire. At the end of the first leg, I stopped at a CA Ford shop for a bit of diagnostic help. Two hours and $147 later, they told me I had an "intermittent high- resistance or open circuit on #8 injector". They also wanted about $800 to fix the problem ($490 labor + $314 parts). I responded politely that I'd be taking my truck elsewhere. After I got the rig home, I tore off the valve cover, looking for a busted wire. Meter found no problems, so I called the local Ford shop about a new injector harness ($42 for harness, $57 for gasket). In the process of cleaning the existing harness, I noticed that all the connector sockets were deformed. Using a heavy-wieght sewing needle, I bent all the sockets back to square & closed the gap slightly. Since the gasket says "reusable" on the top, I just cleaned it off. Put everything back together & it runs like a top.

Moral of the story? If you're only slightly mechanically inclined and have a few tools (including a sewing needle), you can probably fix your own misfires. And stay away from northern CA Ford shops!

Afterthought... The parts guy at the local dealer said they sell LOTS of harnesses and very few injectors. Hmmm, wonder why...

 

That's a great story, and thanks for sharing it. I recently had a big misfiring problem as well, and had to replace the internal wiring harness, valve cover gasket, and also replace the harness connector on the outside of the valve cover. I'm not McGyver, so I had to actually buy parts, but saved a ton of money on the labor a shop would have charged for the repair.