I have a 99 F-150 4x4 OFF ROAD with a 5.4 Triton that has just been rebuilt .... new pistons,rings, valves, etc. There is a problem with something, and I can not find it. I don't remember the exact code numbers, but there are 3 particular ones.... coil pack A, B, and C not firing. The last time I had a problem with my coil packs, the codes read that coil packs 1, 2 etc. were not firing. I have not seen these codes before and neither has any one I have asked about this.

The motor keeps miss firing, and just running poorly. I have checked the easy coil packs to change and they are all firing.

I have found out that I can unplug the #1 coil pack and it will not make any difference in the way the truck runs, misses with the pack working or not.

I would really like any help any one can offer.

Here are the 4 things involved in a cylinder firing on our mod motors...

1. Spark plug (obviously) try moving the plug from #1 to #2, since they are both easy to get to. IF the miss moves you know its a plug.

2. Coil. Try moving it as well, but only do these one at a time so you can narrow it down.

3. Injector. If the coil and plug move doesn't yeild the results then try re-locating the injector in the same fashon. Make sure you get the O-ring with each injector top and bottom, otherwise its a mess trying to re-install them.

4. Wiring at the plug. Check to make sure your connection is good at the coil. I have seen the little clip on the plug break off and you don't quite get it down all the way.

IF these things DON'T fix your issue, then pull compression on the cylinder. You should be bouncing at about 150 psi. But anything over about 120 psi is acceptable. If you are concerned about your compression you can pull it on the other cylinders also to give you a base line.

Compression would tell you if you have a leaky or improper valve seat. May also wanna pop the valve cover off and make sure your rocker arms didn't slip off the cam.

Anyway that gives you something to go by. If you have any other questions feel free to hit me up. I have been inside/and around these motors quite a bit.

I have another question .... if i take my cat converters off of this truck, will it still run correctly ??? I am planning on keeping the front and back sensors in place, just put new pipe in place of the converters. Mine are stoppin up and can't find any good cheaper ones to replace the OEM cats with...

Just change them out with high flows from ebay. I have had mine for 4 years and have had no issues. I would NOT run these without a cat.

What is the brand you are talking about ?

The thunderbolts look comparable to the ones I have. IIRC the stock exhaust is 2.25 just for an FYI.

I finally got this problem fixed ..... it was an EGR soleniod.