What could cause an ignition coil to lose spark at 2 cylinders...twice?

Donna · #1 10-01-2008, 03:31 PM

Hey guys, I was wondering if anyone could tell me what could be causing the ignition coil on my 2002 F150 4.2L to go out. I have been having a few problems with this truck already, terrible shuddering when in gear, really bad fumes, absolutely no power. Found it to be the coil pack, had 2 dead cylinders. So I bought a new one, and it drove fine for the day, then when I started it up again (the same day) it was doing the same thing. Checked the ignition coil again, and found 2 different cylinders had no spark. I bought a new ignition coil, but now I am scared to drive the truck! haha, I don't want this coil pack to go out too! Anyone got any ideas? Anything I should be checking? Thanks.

Also to add, before the truck started running bad the second time, while I was driving, the throttle body cover somehow got caught up under the throttle positioner and the truck was maxed out! I panicked at first and didn't know what to do!

I was standing up on the break, freaking out thinking my truck was possessed! haha, I pulled it over and put it in park! BAD IDEA!! The motor revved up so high it sounded like it was going to explode! I shut it off, jumped out of the truck, and waited for it to explode. Seriously, I was scared to get close to it! haha, eventually, when the truck did not explode or burst back into flames, I tiptoed back over to it and popped the hood. That's when I discovered the problem was the throttle body cover and not a demon.

Whew! Could this have caused the second ignition coil to lose spark at 2 cylinders?

glc · #2 10-01-2008, 04:42 PM

Sounds like you may have bought an offbrand coil pack - like a Duralast from Autozone. Those are junk. I'd try to return it as defective and exchange it. Make sure you use dielectric grease in the wire boots, and if the wires are old, replace them.

Donna · #3 10-01-2008, 08:44 PM

Also, what could be causing no power at the crankshaft position sensor. The neighbor told me it could be causing my problem, so I checked the voltage on the plug but there was none.

flip4x4 · #4 10-01-2008, 09:06 PM

Is it throwing a cel???
Did you replace the wires and coil? I would do it all at once. Plugs, wires, coil. The stock coil goes crazy if it gets wet at all. like car washes, ect.. I use a duralast coil and i mud i have had no problems at all.
As for the crank sensor try v6f150.com

glc · #5 10-01-2008, 10:52 PM

If the CPS goes out, it won't even start. It won't knock out 1/3 of a coil pack.