Ok hopefully someone can help.

I put a MAF kit on my truck a few weeks ago, in which I messed with the spark plug wires. I thought you needed to move a few, but you don't, so I put it back. I didn't have time to put them all nice and neatly away, but it was running fine (very tired after that install). I drove it for a few days and it had a very slight miss firing on load, figured it was my crummy spark plug wiring job so I didn't think anything about it. Then my side/spider gears decided to go on me so I took the truck off the road for 2 weeks to fix it. When diagnosing the rear end problem, took it apart and put it back together and tried to drive it (before replacing it). The truck was running horribly bucking and jolting. I thought it was the rear end so I drove it right home and parked it. In aftermath, it must have been the motor. When finished with the rear end, and drove it, it was missing under load. So after the MAF kit it was running fine, and I havn't changed anything under the hood during the axle install. I played with the wires, re-wired it correctly, and it's still missing. I get the feeling its from the wires because the amount of missfiring will change after playing with them. Sometimes it missfires terribly and sometimes its ok and will only misfire on large hills. Today I took the time to wire them as perfectly as I could. None of the wires are touching eachother but it's still running like crap. I followed the sticker on the radiator support and I can still barely drive the thing, any ideas?

 

With the HO firing order, which wires do you have to worry about crossing as that would be different than the stock firing order. They just have to not touch eachother right?

 

maybe with all the changing and stuff the wires went bad, probably worth just picking up some new ones to see.

 

maybe your 180 degrees off

 

With the motor you have now, the 7 and 8 wires are still the ones to keep separate. The engine firing order is still the same. The injectors are the only thing that are in the HO firing order. They could be your problem, firing out of sequence. Does it miss at higher rpm's (above 3000)?

 

no..it will miss at any RPM...under load...the truck will buck because it's a standard tranny. After the MAF installation it was running almost perfect..wasn't miss firing like this, so the injector sequence is not the problem. I havn't touched the distributor..so it's still ok...and the miss will get worse/better if i play with the wires. Whats the trick to the wires...the 1-4 cyl are tricky because right off the distributor they have to cross eachother. According to the sticker...1 goes under all of them...and 4 goes over 1..but under 3...and 2 just goes straight....the are crossing eachother here...but right now they are not touching eachother (difficult to do). The 7+8 are running next to eachother but...if they touch its barely...they don't cross eachother...I have separated all the wires w/ the little spacers.

 

If the wires have to cross, cross them at 90 degree angles. This will minimize or eliminate any induced cross fire. Running parallel is when the most current can be induced. Are you still running the MAP sensor, or did you disconnect vacuum on it? Also, another thing I thought of, maybe not related to this, but anyway, the TAD and TAB solonoid pins are at different locations between the Mustang computer and the truck computer. I assume that the overlay harness from the kit took care of this, but it might be worth looking at, and could be the cause of your check engine light.

 

Is your firing order 13726548? if it is #5 and #6 can't be anywhere near each other except to cross at 90 dgrees at the cap.

 

OK maybe it's this 90 degree thing, I have few that are not 90 degree. I'll try that and see what happens. I did disconnect the MAP sensor hose per the installation instructions. I've still got to check my computer codes to see which one is popping up, but when I get a chance I will.

 

Real simple test, wait until dark and have the truck parked in the darkest area you can find and start it and check under the hood for a lightning show! If you have a wire shorting, you'll find it! That will also help you find that elusive broken insulator on the plug, might not be a wire problem!
Al

 

I have uploaded some pictures to my gallery. If you guys need me to help make sense of the pictures let me know. Is there anything you can pick out wrong with my wiring job?

https://www.ford-trucks.com/user_gal...8&albumid=9791

 

One thing I just thought of, have you checked plug gaps? My truck has developed a miss, and I can hear the spark arcing out of the wires. I'm going to check the gaps tonight, and since you had a similar problem, I thought it might be one more thing you can check too.

 

I just put new plugs in a few weeks ago..gap should be fine. I might have damaged a wire or two installing them but..i dont get it..it was working ok after i put the plugs and the MAF in.

Well I just went outside since its night time and took a look at the wires while the engine was idling. The 7-8 were arcing a small amount at a point they were about 1/4" apart and..at a 90 degree but they still arced a spark when I wet them. I also noticed a little arcing on the #5 plug next to the spark plug. It was arcing to the block. I wonder if I should just buy some new wires and try that?

 

Looks like #1 and #3 are touching ever so slightly, separate them with #4.
Gallery?

 

If you're seeing arcing, I'd lean VERY heavily towards buying new wires. What wires are your running now?