cross-post from PBB...


The patient: 1996 T100, 3.4 (clearly), auto, 4x4 w/ 140K miles. Very clean truck for MN with zero rust, other than the standard chassis rust. Owner installed an aftermarket head unit and Envoy brake controller w/ 7 pin connector for pulling his small enclosed trailer. Truck is otherwise stock.

I've had the truck since January, and it's been driving fairly well. Averaging about 18.5 mpg. Truck received new wires, 2-electrode plugs, oil, filter, etc, etc this Spring.

I have a 2007 PJ 18' car trailer that I purchased brand new last year. Love it and it works well.

Last Friday (08/01), I put my John Deere 2305 on the trailer and pulled it over a friends house so he could do some garden work. Truck pulled it (about 1500-1600? lbs) w/o a problem. Parked the truck that night with the trailer connected and it sat until today.

Started it up today and it ran like CRAP. Felt like it was running on 4 cylinders - thought I lost a coil pack. Had to drive to my friend to pick up the tractor anyway, so I punted and drove it over. Trailer felt like 10K lbs behind me and I was getting no where fast. Check engine light turns on; solid first, then blinking. I count 5, 6, 12, 13, 21, and 33 blinks, roughly. Can't find anything obvious at his place.

Load up the tractor, get it back here and the truck is just hating me. As soon as there is load (hill, accelerating), the check engine light starts flashing. Unload tractor, park trailer and get ready to head to town to borrow a scanner from a parts store and prepare for the likelihood of having to buy coil packs at $150+ each.

But the truck is running great. Check engine light is still on, since it hadn't been cleared, but no flashing, no rough idle, no nothing. Runs like it normally does. WTF? <img src="/forums/images/graemlins/confused.gif" alt="" />

Scanner says miss-fire on cylinder #5. Haven't been able to get it to trip again since unplugging the trailer - it's running great.

What. The. Hell. ?????