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Missing on #4 solved, I think.

Hi: I've got a '99 F-150 Lariat 5.4 L 4x4 auto with about 57000 miles on it. A month or so ago it started to run and idle roughly, especially during light acceleration. The problem was fairly intermittent at first. I tried better gas and injector cleaner, and replaced the air filter. I bought the truck used with a K&N filter, noticed that the gasket was bad, and decided to just put a Fram filter in instead. No improvement. At some point, the check engine light had come on, so I took it to a shop. They said it was missing on the #4 cylinder. During the course of trouble shooting it, they put it all back together and took it on a test drive. Wouldn'tcha know, it ran just fine. They charged me for one hour of Dx and said to bring it back if it acted up again.

Anyway, it started running poorly within a day or two, and gradually went from intermittent trouble to running badly almost all the time. Based upon what I could find on this NG and F150online archives, I decided to try replacing the #4 ignition coil, as that seems to be a fairly common culprit.

I'm not much of a mechanic, I'd never done much besides changing my oil, so I'm pretty happy to report that I seem to have solved the problem.

The coil was about $60 at Action Auto Parts. It seems to be running great! I hope it lasts....

It sounds like the #4 coils goes bad fairly frequently. Anyone know why? Heat or moisture? Any ideas to correct/prevent this?

-- Josh

Reply to
JDub
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Cool post thanks.

How's it look to you? What's different about the placement of the #4 and the others? Does the coil pack look different from the others?

If it's heat, is there room to put a heat shield (thin sheet of steel) between coil pack and the heat source?

I'm a fan of Standard Ignition products and their "Blue Streak" line. Might try their stuff if it happens again?

Alvin in AZ

Reply to
alvinj

Well, it's really close to the firewall, behind and under the back edge of the hood, so I suppose it probably doesn't get as much airflow as the others. It's also under a couple of hoses, maybe moisture is getting in there? I'm inclined to think it's the heat, though. It seems to me that moisture wouldn't find it's way into the coil so much as the spark plug well?

As for the coil pack itself, I thought all 8 were the same, but when I removed #2 and compared it to #4, they were a bit different: At first glance they are identical, but when you remover the rubber sleave you can see a difference. They each have a coiled spring with a solid metal rod. Both the bad coil and the replacement part for #4 have a spring-rod-spring configuration. That is, the spring is about 3" long and the rod is inside the center of it. The #2 Coilpack was about 2" of spring with a rod on the bottom end of it. Clear as mud?

I don't know what that means. Maybe the #4 had already been replaced by the previous owner and that's just how the after market part looks?

Thanks for the input.

-- Josh

Reply to
JDub

It was suggested at one time that condensation from the Air Conditioner could drop on the coil. That does not seem applicable for this time of the year.

Reply to
Mellowed

Reply to
Fritz Blackburn

I couldn't find any reference to a recall/bulletin, but lot's of truck owners have posted about the same problem. I just cleaned up the old coil pack that I replaced and sure enough I can see a tiny crack running accross the top of it. The clamp on the heater hose is an after market screw on type, so I'm thinking that the previous owner had the same problem, but didn't get the clamp on tight enough when they fixed it?

-Josh

Reply to
JDub

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