99 Explorer miss-fire..again!

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Jul 31, 2006 | 07:40 AM

tibailey

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From: Kirtland,Ohio

99 Explorer miss-fire..again!

I'm getting a miss-fire on start-up. The Check Eng. light is on and the code that I got is a P0304. This is the 3rd time that I have have seen this code. The Dealer has done the plugs, wires and the coil pack. Am I now down to a fuel problem? Looking at my past records I can't see when they've done the fuel filter. I remember doing a fuel filter on a Jeep of mine some time ago. Is it a simple job for me to do on this truck? What else am I down to to do with this trouble code?
Thanks, man ahead of time.

Jul 31, 2006 | 09:29 AM

tibailey

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From: Kirtland,Ohio

Forgot to mention injectors were replaced @ 98,000 and the fuel filter was last replaced @ 63,0000.

Aug 1, 2006 | 01:05 PM

allan1010

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P0304 is a misfire on #4 cylinder.
The codes for misfire are easy to diagnose: P0301 thru P0306 depending on which cylinder it is.

It is possible that a new plug or wire (or even the coil pack itself) has failed. And it's not beyond the capabilities of some dealerships to fail to properly seat either end of the plug wire.

Try this; clear the codes with your scan tool if you have one or by disconnecting the battery and leaving it for 30 mins.

Check the plug wire on #4 at both ends to make sure it's seated properly and if it is seated then unplug it and swap it with a wire from #5 (or any other wire of similar length; you need to be able to reattach both wires at both ends).
Now start the engine and see if the code shows a misfire on a different cylinder. If not, try swapping 2 plugs and repeat.

This will eliminate the plug and wire.

I don't think you have a fuel pump or filter problem; that wouldn't show up on just 1 cylinder.

Aug 1, 2006 | 02:58 PM

tibailey

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From: Kirtland,Ohio

allan, Thanks for the "heads up" on the wire seating". But,I took to a Ford Dealer today and showed them all that had been done on the truck. Told'em after spending nearly $900.00 over the past year on this code/miss-fire problem I deserve some kind a explaination. So they looked over the truck for 2 hrs.and came to the conclusion that one of the injectors might have a slow leak, allowing fuel to drip on past when the engine sits cold. I have a shop in mind that does injector rebuilds, so I'll take the truck there if missing gets too out of hand.

May 25, 2010 | 09:11 PM

j891035

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Joined: May 2010

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Miss here too.

I also have a 99 Explorer and for the second time in like 4 months it has started missing again. I just replaced ALL of the plugs and wires like 3000 miles ago. The code shows up as a miss in #3 and #4. I have re seated all the wires and even changed the coil pack to no avail. I have ALL 6 injectors replaced last year after one went bad. Now the motor shakes something horrible. I pulled all of the plugs but saw nothing that looked bad. When I did the plugs last time I replaced them with Autolite Dbl Platinums and it ran great for the last coouple months. Then all of the sudden it went gunny sack again....Any ideas?