P0303 Code - Cylinder #3 Misfire.
 

Well, while driving home about 2 weeks ago. At speeds of 60MPH or 70MPH
I notice my engine light started to blink several times,
until it stop and staid on. There was some hesitation too.
When I got home, I took my hand held Code Reader and it came
with this code ---) P0303 Code - Cylinder #3 Misfire.
I had this truck for over 3 years now.
I have never had any problems with it.
Other, than blowing the rear differential.
I have never tune it up other than regular oil changes at 3000 miles.
I was waiting until code came back on.

Well it came back on today at the same speeds of 60MPH or 70MPH
It was running so good that it’s even past inspection and emissions on (11/30/07),
with no help what so ever.
I guess it about time something when wrong.
My 1998 Ford Expedition got 120,000 Miles and going strong...
I should just give it a tune up.
I stop at AutoZone and pick up Motorcraft spark plugs at $9.99 each plus tax.

WOW, I didn’t realize they were so expensive.

I didn’t pick wires up due to them look brand new.

I guess I will find out tomorrow morning when I tackle this monster of a job.

Later, Al

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Well, Guys
Here is the update...
I gave up trying to change the plugs.
I will take it to the shop and have them do it.
I couldn't fit my big hand anywhere, unless I took lots of thing apart.
Hell no I rather pay.
Later, Al

So, I guess that years model uses a distributor with spark plug wires and not COPs. If it was COPs I'd say swap the number three out for one of the other 7 and see if you get a misfire on that same cylinder. Although after 120K miles a fouled out plug is definitely a possibility.

Could be a bad coil pack.

www.performancedistributors.com

Wow, the Motorcraft plugs were only $3.99 at my Autozone.

You know what's funny is....
It had 98K miles on it when, I bought it around 3 years ago.
I look inside the hood and it looks like the previews owner did some work to it.
I saw new wire and new plugs at the time.
So do you guys think I should still tune it up after 22k miles I put on?
Or could it be a bad coil pack?
And if so how can I find out for sure. Since it only has two coil pack and not eight?
Thanks in advance… Al

Well, Guys
I was trying to hold on until weather got warmer but it’s getting worst.
Now I’m getting two codes, PO303, PO304.
It feels like it’s running on six cylinders instead of eight.
I had to park it until this weekend; I’m going to try doing it myself.
I shop around and return the Motorcraft spark plugs at $9.99 each from Auto Zone.
And, pick up the Motorcraft spark plugs at $5.00 each at another store.
I have a question? What spark plug wires should I used?
Reminder, I have a 98 Ford Expedition with the 4.6L motor.
Thanks in advance, AL

I'd recommend going with Motorcraft. Should run about $100 for the set.

Well Guys

I finally got the change to change the plugs and wires. Boy it wasn't easy. It took me 4 hours, due to after putting new plugs in the socket. The socket keep getting stunk on the new spark plug and boy it was a pain in the ass trying to get socket off. I did find a secret weapon, before installing new plug on socket put a small amount of white crease on socket this will help make socket slide out more easily. It works great on #3 and #4 especially since you won’t have a lot of room to work with.
I install Motorcraft Platinum Spark Plugs, and Bosch Platinum Wires.
It runs like new. I also found an article on the installation after I was done with mines. It figures.

How To Change Spark Plugs on 4.6 & 5.4 Liter F-150s
By Dave West

If anyone needs it let me know and I will repost it.
Thanks for all the help…
Al52269

Like I say in my post on my experience with changing plugs for the first time, you are better off doing it yourself because you will never know if a shop actually changes #4 and #8; only someone who has done the change themselves would know: https://www.ford-trucks.com/forums/6...ml#post5499863

My eyes hurt after reading this thread.

Dagnabbit....My wifes Ex is pulling the PO303. I guess I know what I am doing for my vacation.

"How To Change Spark Plugs on 4.6 & 5.4 Liter F-150s" , thanks for the post and link

question about this error code, since changing all the plugs is a PITA, could I just change #3 to see if that fixes my problem. and if it fixes it then do a whole plug change.

The whole top end was went thru 20k miles ago, I would thought they put in new plugs at that time. HOW do I know which one is No 3. does it start on the drivers side from front and move 1 to 4 then pass side 5 to 8? or does it horse shoe? or does it start like reading a book, from pass side to drivers side? sorry, but the manual i have just says change plugs, remove all plugs, there are pics of the plugs coming out of the holes without any information on which is considered #1 or 2 or so on. I just had a thought, I need to search these pages to see what the cylinder numbers are, that would tell me where no 3 plug is.

thanks

Knix

found my answer again, thanks

Racerguy
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Recently purchased Autolite platinum plugs at Walmart $4.42 pair. Best price I've seen anywhere. On my vehicle the problem was a spark plug wire.

Russ

Spark plugs
 

I have a 97 Mountaineer and found it's easiest to to access the spark plugs through the fender wells. Remove the front tire and rubber splash guard. Should take about an hour to replace all plugs.