2000 Expedition 5.4L. All of the sudden the vehicle started running rough. After awhile the CEL came on. Then the CEL started to blink. We were in the middle of nowhere, so we had to drive the vehicle home. Took it by autozone and it shot P0306 and P0307. I thought it was water in the fuel. Poured some isodry down the tank and nothing. Vehicle has 56,000 miles. Plugs and wires are original. I have had it at dealership just for oil changes and regular maintenance. Never for problems. 1st problem. The vehicle was parked in a snow storm. I reset the computer after finding out the codes. The engine still runs real bad and there is no CEL. I do have an ESP (Extended Service Plan) with a $100 ded. I'm not sure what to do? Are plugs and wires covered? Are coil packs? I can do the work myself and get ford parts wholesale, but if ford will cover it for $100 bucks I'll go there. Any counsel? I am also afraid the cat is toast just from reading the other postings? Will ford cover that? How do I know it is bad? How much are they? Sorry, for so many ?'s. Please help?

 

Have you changed the fuel filter on this vehicle? If not I suggest you do so....If this does not solve your problem, then I would test the coil packs...But definately change the fuel filter first.....

 

Thank you for your response. The fuel filter was replaced about 11,000 miles ago with a motorcraft filter. I don't think this is it. All cylinders would be misfiring. Right? According to what I have read the codes say cylinder 6,7 are misfiring?

 

Then I would check those two coil packs for starters..

 

Just my $.02: take it to the dealership. $100 ded and they diagnose the problem(s); all parts mentioned cost more than $100 (plugs/wires, 2 coil packs, 1 cat). I've had the Ford house here tell me, "$85 to hook it up for diagnosis, parts and labor for the repair are not included in the $85.00." The fix, I'm sure, is a simple one and you don't want to "shot gun" a bunch of parts.

I've had a Ford extended warranty: starter went bad and took out the battery: Ford replaced the battery also because an under-warranty item caused another item (not under warranty) to fail. You should check your warranty to see what items are covered(plugs/wires - probably not; coils and cat should be).

Are all plug boots SECURELY attached to the plugs? I've had 1 pop off and it ran as rough as a cob; crimped the terminal, haven't had a problem.

I don't know how long it will take the water to completely "flush" through your fuel filter; there is no coasceler feature such as the fuel system on diesel models. I would change the filter; you may need the fuel filter/ac tools to remove the filter and the tools are available at Pep Boys, Advance Auto, etc..

You also mentioned gas dryer: I use 7 oz. of acetone to every other tank of gas. Go by your paint store and get a can. It won't hurt any parts, it helps combustion, and it will help with any water in the tank. Lubedev.com Articles is my source for acetone.

Best of luck,
Curt

 

I'm going to call the dealer this morning and look at my warranty. I'll let you all know. Thanks. Is changing the spark plugs as scary as it sounds? Should I change them now? Should I change the plug wires? Keep the advice coming.

 

In general, problems like EGR, EVAP, vacuum leaks, plugged cats, fuel pumps, fuel filters, fuel quality/water will affect all cylinders and set a P0300 code (random misfire).

Problems that affect a single cylinder like injector, coil, cracked head, head gasket, and single cylinder mechanical problems will set one or more specific codes like P0301-P0308 where the last number identifies the misfiring cylinder.

OBD isn't perfect, so odd things can happen.

Your problem could be a number of things, but coils aren't unlikely.

 

Oh yeah, a long term misfire feeds raw fuel and unconsumed air into the cat which burns it there. Enough of this can ruin a cat or even burn through it. But it would probably take more than a 100 miles with a solid misfire to affect it. If you suspect it, we can offer a series of tests for it being plugged, for it not passing an emissions test, or for it being burned through (sound/smell test). But if no light and you don't live in an emissions testing area, and you don't loose significant power (from it being plugged), just drive it.

 

you have coil over plugs so checking the boots is not an option.

yes changing the pulgs on an 5.4 is a nightmare!

there are a lot of things to cause missfires on these trucks and there are a lot of common problems that happen on each year/model/engine

some of the more common problems with your truck engine combo are:

dirty maf
collapsed pcv hose
coil pack shorting because of water (Usually #3 and #4 though)
intake leak

anyone have any others?

also on these individually fired and fed modular engines you don't really have to worry about a lot of fuel blow by. the ECM will stop most of it.

later-

 

My dad had the same problem with his 99 f150, It has over 170,000 miles and the idle became very rough all of a sudden. It turns out that the coolant hose had a pin hole leak and coolant shorted out the coil for the number 4 cylinder.

 

Well I took it to the dealership and paid an $89.00 diagnosis fee. They said it needed a tune up. The coil boots were cracked and there were carbon tracks on the spark plugs and boots. Funny, my original sales brochure says that the Expedition does not need a tune up for 100,000K. Whats up with this? So, I purchased 8 coil boots, 8 spark plugs and some dielectric grease. My cost was $107.00 for these parts. Hopefully this fixes the problem. Any help out there for changing the plugs? Especially #4 and #8.

I did contact Ford's "We don't care if you are a Ford customer" customer assistance line. They said, "yada yada yada, we will not cover the tune up that the dealer says you need, even though our sales brochure does say that you don't need a tune up for 100,000K." Deny the claim, always say NO. Deny the claim. NO NO NO NO.

Thanks for the help. I'll let you know the result of the tune up.

Stephen