I have an '01 f-150 4x4 with the 5.4 triton and auto trans with the tow package.

I was driving friday afternoon and it started bucking and acting gutless, I let it coast and the truck seemed to smooth out, I accelerate and it came right back. I drove like this for a few blocks before the check engine light came on. I shut the truck off and let it sit and could smell that lovely smell of eggs coming up from under the truck.

I brought the truck home and noticed that when it was under load it would smooth out but not have the real power it usually does. I let it sit all weekend and started it up now and it was fine for about 5-10 mins then it started all over again.

I went to the "zone" and used their reader and it showed one code of misfire in # 6. I went in and talked to the guy at the counter and he said that everything except the smell sounded like a failed plug. But he did say that if the truck was dumping the unburnt gas in to the exhaust it "could" cause that as the cat is working harder to clear it. He said that a failed cat should show as a random misfire on all cylinders and not just one.

Now everything with the exception of the mis-fire on #6 sounds like a failing cat to me. But that is why I am here to see if others know more about this than I do.

Also I am trying to sell this truck so I dont want to sink a fortune into it... and I live in a "CAT" required state. ;(

 

If you don't fix that #6 misfire, you will permanently damage the cat. Keep overloading it with unburned fuel an it will go south in a big hurry.

New COP, Autolite or Motorcraft spark plug, and some extra dielectric grease in the boot will probably fix it.

Just need to hope that the cat hasn't been permanently toasted. Avoid driving it if at all possible until repaired.

Steve

 

OK thanks for the resonse, I think that the total amount on the engine since it happened was only 20 mins+-, that included the day I noticed it and today. I wouldn't think that little bit would have burned out the cat, but will know soon enough.

Also the COP looks like it is hidden under the fuel rail, does that (the fuel rail) have to come out to get the plug out?

To clarify that is the second plug back from the front/radiator end, and the left/drivers side correct? Hate sounding dumb but dont want to pull the wrong one and have it be counting from the firewall out.

 

Yes second plug from front of motor on drivers side. Fuel rail should not have to come out.

 

i'd pull the fuel rail, makes it so much easier and only takes 30 seconds. It sounds like your coil is dropping off under load to me.

 

Swap that COP to another plug and see if the misfire code moves, this will tell you if it is indeed the COP that is bad.

 

If I'm not mistaken a Cat code would come in the form of a failed bank code. I agree with the others check the COP and go from there.

 

I just had the EXACT same problem a week or so ago. My truck was misfiring and the exhaust stank. It ended up being a COP. I would change out the COP. You do not have to remove the fuel fail. And just to confirm what everyone else said: number 6 is the second one back on the driver's side.

-Matt

 

i wouldn't pull the fuel rail - the cop bends out easily once unbolted and unplugged.

 

OK I got the plug in ($4.00) new spark plug socket ($6.00), COP ($40.00). Total time between running to the store for the plug and socket, searching for missing tools and laying on my face to do it, about 2.5 hours.

Wow remember the days of doing all 8 plugs, cap, rotor, and an oil change in half an hour and complaining it seemed to take too long.....

Got it all back together and it started right up and is running smooth will take it out and road test it and see what she does. Also noticed that the Service engine light did not go off, assuming that it will reset itself? If not will go back to the zone to have it cleared. Also did it with the fuel rail in.

 

The SES light will eventually go off provided the PCM executes enough consecutive self-tests without a failure.

I'd just reset it with a scan tool asap so that you can then determine that, should it come back on, that another fault has been found. If it is left on to (maybe) reset over time, it may mask another condition that you would otherwise be unaware of.

Steve

 

Well road tested it last night and it appeared fine, nice and smooth. Drove it in to work today and it would have acted up by now and still smooth so I think we have it.

SES light is still on will take that to the zone to clear it.

Thanks to all for all the great advice, it was alot easier of a job to do than anticipated. Lets hope that no more go cause I can't even see the ones behind that one...

 

Yeah, #7 & #8 are a lot tougher as is #4.

Steve

 

disconnect the battery and cel will reset

 

I thought 7 was the toughest cause of whatever that blob is in the middle of the fuel rail right near it. I had to get a thin headed 1/4" swivel head rachet to get the COP bolt out. After that it wasn't too bad.

Seems like you might want to change the other plugs now so all 8 are new.