Got the same goin on here... #4 misfire. Happened on the way home limped it 10 miles to the house. Used my new Innova 3110 CAN OBD2 Diagnostics ...... Mis-fire #4. Got up this morn started truck...NO MISS! Let get to operating temp NO MISS! Test drove 1/4 mile miss appeared and Code came up for Random Mis-fire. Cleared the code drove again it gave same as last night Mis-fire # 4...... seems the cop is failing under demand and then it fubarbed untill cooled. Im fairly confident its the cop(#4) being that the plugs are new under 1000 miles. Seems to me these cops are notorious for failure at the age of my engine.....(around 100,000)107,000. Advance Auto>Sorenson< COP $ 44.90 =tax 1 yr warrenty. Im goin to replace it in the morn and Ill come back with results....... BTW, the CEL never came on at anytime... weird!

 

I had it happen on No. 2 on 97' 4.6 after loads of rain. Turns out water around the plug shorted the cyl out. I swapped out all the wires and plugs. I was concerned about the coil but it seems to have survived...

 

Replaced the COP this evening...cleared out the code and fired it up.........Problem Solved. I did not find any water on the old COP(origional from factory). It took about 10-15 mins to replace. #4

 

Sorry to dig up this old thread...
I've got a 2002 with a 4.6L at 93,000 miles, recently got a flashing CEL, followed by a steady CEL on the way to work. Got it scanned two weeks ago: P0303 (Misfire Cyl #3). The dude cleared the CEL, but the truck kept running rough (I haven't been driving it much).

Today I pulled the COP and installed a new one (with plenty of dielectric grease inside the boot). The old COP actually tested good across the primary terminals (.6 Ohm) and secondary terminals (5.6 kOhm), but looked pretty worn out.

The truck revs smoothly in park from idle to 4,500 RPM. It also revs pretty smoothly while driving and at highway speeds from 1,500 to 4,000 RPM, all with some slight bucking.

I can't tell if the engine is still missing on Cyl #3 and not triggering the CEL because the whole truck vibrates due to the mud tires. We'll see if the light comes on this weekend.

Probably time for new spark plugs since I'm almost at 100,000 miles?

 

Yea, it needs a tune up.

 

I'd change the plugs, coils and injectors if it were me. Do waste your time checking across , ohms/resistance. Only Primary failure can be detected that way which usually isn't the case. You can check for 508 resistance using the selection with a meter. Still, the coil may be fine with scoured readings.

You can find these parts cheap on Ebay and if you include new O2 sensors to your tune up, that covers just about everything besides the normal crap. Like Motorcraft PCV valve, Air filter, Fuel filter and what not.

Check the pump as well. The factory fuel pumps can go out about then, 90,000 miles +.

 

BTW- Ask here where to get the parts, if you can't locate them. The right parts can make all the difference.

 

Got a Cyl#8 misfire this week, time for 100K tuneup a little early.

Gonna try to change the following myself:
-Motorcraft Spark Plugs AWSF-32P
-Motorcraft PCV EV-258
-Motorcraft Serpentine Belt JK-6996E

And have the following done at an auto shop:
-Transmission Flush and filter change
-Coolant Flush
-Fuel system service (clean injectors, throttle body, intake)

Oil, oil filter, fuel filter, air filter, transfer case fluid, differential oil (front and rear) have been done recently.

Is doing the spark plugs myself feasible (I've done them on a 99 Mustang GT with the same engine), or should I bend over and pay a couple hundred bucks to let someone else hassle with them?

Do the 02 4.6L's have the nightmare spark plug issues the newer engines have?

 

Good deal!

Plugs, = No, they don't break, BUT, you have a COP ignition, so be thorough with how you do that. Old coils, I'd label them and install them back onto the SAME cylinder they came from. Grease them up well to focus pulse to plugs correctly, - that also saves your boots from all those nasty carbon trails that break down the silicone.

Start all the new plugs with a scrap piece of 3/8 air hose, IF you don't want to take any chances screwing up the head threads, - that's to easy to do unfortunately.

Plug torque is 28' lbs. Absolutely DO NOT go by Fords workshop/manual spec here. Use the 28' lbs spec. You'll be golden.

You can do a much better job yourself as a dealership tech would be limited to two hours max and usually will only do what they have to. However, that's fair and to be expected. They're just not paid to take the time you can afford with this type of thing.

There you go, - questions ?

BTW- Your GT has this engine? If so, it's a different ignition set up.

 

Jbrew, thanks for the feedback. My 99 GT had a 4.6L similar to the F150, different cams and tuning though I believe.

How do those part #s look? I think I'm ready to tackle this one soon.
Also, I should NOT use anti-seize, correct?

 

Parts look great! NO anti-seize. Absolutely not.

What I meant, -the 99 GT has plug wires and coil packs. The truck doesn't, - truck doesn't have plug wires or coil packs. It has coils, that's it.

 

Definition of "coil pack" according to jbrew = a coil assembly that feeds multiple cylinders using traditional plug wires. Coils that are individual and sit on top of each plug are called COP = coil on plug.