Code P0301 (misfire) troubleshooting
 

Just bought a 1997 EB Expedition, 5.4 engine, 148000 miles..

I'm getting a code P0301 (cylinder 1 misfire detected).
The engine idles a bit rough and lacks full power.
Can I assume it's either a bad spark plug, bad #1 coil, or clogged #1 fuel injector?
To start the troubleshooting, I was going to move the #1 coil to the #2 position and see if the fault follows (unless someone knows how I can check the coil with a VOM, I'd need to know which pins to touch and the expected values). I've read the other post about the bad boot info. Will check that also.
If it didn't follow, next I would change the #1 spark plug.
If that didn't cure the problem (code), next would be to check the fuel injector. Not really sure how to check them.

Can someone also verify the #1 cylinder is the front/right cylinder (or closest to me and to the left as I stand in front of the truck)? I bought the Ford service manual on CD but couldn't find the cylinder order anywhere.

Am I one the right track? Any tips or advise on the subject would be appreciated.

I'm currently replacing the upper and lower ball joints and will be tracing down a bearing noise that occurs while in motion. Hopefully it will be in the right wheel hub (I have the left off now and it feels fine). Really hope it's not coming from the front differential.

Just want to be prepped to do the engine after I finish the suspension work.

Ken

replace the spark plugs. If that doesn't do it, then you need a coil as well. Motorcraft only.

4 8
3 7
2 6
1 5

Front


Replace the plugs with Motorcraft or Autolite double platinums. Clean the MAF and change the PCV valve, then go from there.

missing in overdrive
 

I have a 99 f250 4.6 4x4 with 48,000 mile ,it starts missing when going up little hills at 60 to 65,Turn off OD run fine

Could be moisture in a plug pocket ot a bad coil boot, or even a dity MAF.

Ken, do what you were going to do first. The easiest thing to do should always be the first step ;) Sometimes.

It'll take you a few minutes to swap them. When you pull that #1 COP make sure the boot is dry and no crud all over it. You might just have a wet hole ... :-missingt

If you already have a problem, and it's obvious what cylinder it's in, there's no reason to start swapping all the plugs at once without making absolutely sure what the misfire is. You could create more problems than what you had to begin with.

As to the bearing noise, have fun ;) Is the right one loose at all?

I would have to agree with JH6 replace plugs first when was the last time they were changed?

(apologize for the double post, I thought this was the better thread to put this info in)

Update....


Swapped #1 and#2.. Problem moved to #1. Purchased an authentic motorcraft DG508 coil from dealer (lots of fake "OEM or "OE" Motorcraft coils being sold online, see below). Anyway, that cleared that problem.

Then... Test drove and got a pending p0303 code. Cleared that code then test drove again to verify. This time got an MIL (check engine light). This time it pulled code p0304. Errr...

Now the plan is to find six new authentic coils at a reasonable price (one was replaced last year before I purchased the vehicle). If anyone knows where I can find them at a discount, please let me know.

I purchased a set of the knockoff's about a month ago off eBay. Price was right at $130 for eight with platinum plugs! Returned them.. Wrong plugs (though the guy guaranteed me they would work, he didn't confirm that he would pay for the overhaul if they were too hot or smacked the top of the pistion) and I also didn't like the way the connector hook up on the coil was made. The authenic motorcraft coils have a little step inside the female portion of the connector that allows the rubber in the connector to make a good seal. The knockoff's do not have this.

Glad I have another car to drive in the mean time...

http://links.pictures.aol.com/pic?id...uPfckq8&size=l
http://links.pictures.aol.com/pic?id...JQ7nU9v&size=l
http://links.pictures.aol.com/pic?id...Zx3JkpW&size=l
http://links.pictures.aol.com/pic?id...iWrgJqJ&size=l

I can sell you some if you like.

Ed

Update..
 

Went to the local junk yard and picked up a few OEM coils. Replaced #3 and #4.
Test drove.. No pending codes or MIL light.
Good power, averaging 13.7 MPG on the short amount of driving I've done to date.
Engine repair involved changing all spark plugs and three COP's (#2,#3, & #4). Removing left exhast manifold and replacing rear most manifold stud. Replacing the two long studs in that manifold that joint the "Y" pipe.

Steering and suspension is like new after replacing upper control arm (with bushings and ball joint) and lower ball joint.

What I thought was a bearing noise turned out to be something else.
There are a few heat shields that follow the exhaust. I found that one of them was rubbing the front driveshaft, making what seemed to me to be a low picthed grinding bearing noise at low speed. Bent it back in place. Noise gone.

The rest should be relatively easy to complete - oil line to remote oil filter has small leak, shift lever on column a little stiff to move, left signal mirror needs replacing, a little touch-up paint, etc..

Thanks for eveyones help, very much appreciated.

All is well for now.

Ken