It seems alot of people are having the same problem I had which I have resolved. So I thought it would be a good idea to post this to possibly save people some money. Mine started out as a misfire problem which I first changed the plugs. I followed the Ford TSB and got all 8 plugs out with no problems. Still misfiring and setting a code for bank 1 catylatic converter ineffectiency bank 1. By the way bank 1 is passenger side. After changing bank 2 because the guy at Advance auto said bank 1 was drivers side. Still setting misfire codes and for bank 1 cat. ineff. So after installing new coil packs and 2 injectors, Still misfiring #3 and #1 and cat. ineff. bank 1. Decided to buy my own code reader, which is a must if you are going to try to work on these new vehicles. Decided to unplug o2 sensor to see where bank 1 really was. Thats when I found out bank 1 was indeed passengers side. Changed o2 sensors. Still misfiring. Decided to buy the true bank 1 cat converter. Dropped old bank 1 cat and found all of the internal workings all broke up and clogging converter. Truck runs like new. I spent 178.00 for bank 1 converter at pep boys. After spending O approx. 600 in other parts that didnt fix it. I think the spark plugs not being changed until 115000 miles caused the converter to go bad. Buy a code reader and it makes it a whole lot easier to diagnose your problem yourself. and save a whole lot of money throwing new parts at it.

 

For starters, welcome aboard, hofec1!!

Thanks for taking the time to sign up & provide that information!! It is always nice to see posts where the owner has tracked down a solution to an unusual problem. For those of us that frequent these forums, it gives us one more useful pointer for some future forum visitor that comes seeking help with the same problem.

 

This is where getting it diagnosed CORRECTLY would have saved u money. Common problem on these 5.4L's. Just did 1 this week. Both banks.

 

I have always said that paying the dealer the diagnosis fee is always worth the 80-100 bucks. As opposed to throwing parts at it and asking the 8.00 an hour Advance Auto Parts clerk what to buy and how to fix your truck...

 

wilber15 you are so correct. I probably would have saved money,BUT the dealers here in the Richmond, VA area have not been so friendly or affordable. Plus i really enjoy working on my own vehicles. I buy a few vehicles a year and try flipping them after making a few minor repairs. These F150's are great trucks easy to replace parts on anyhow. Is there anything I should be paying special attention to that would have caused the converters to go bad other than spark plugs,fuel injectors and COP's. Thanks

 

When u say u replaced the true bank 1 cat what does that mean, since are trucks have 2 cats on each side, are u talking about the bigger cat in the rear?

 

My truck is a 2006 with 1 cat on each side. The build date has something to do with yours having 2 per side and mine having 1. I changed both cats 1 on bank one passengers side and 1 on bank 2. First changed bank 2 thinking it was bank 1

 

My 2006 F-150 4x4 with 4.6L has 230,000+ miles on it and has never given me a single problem. Until now.

I was driving to a job a few weeks ago. She was running fine, like normal, and then, all of the sudden, the check engine light came on and she started missing and lagging. I immediately went to a parts house and had her diagnosed. #3 misfire and #1 misfire. No problem. I bought 2 new coils packs and put them on in the parking lot. No change. She still idled rough, had no power and the codes came back. So, I finished my job, went home, and waited until the next day to do some major tuning.

I bought all eight coil packs, 8 new motorcraft plugs, a new EGR valve with DPFE sensor, a new fuel filter and MAF cleaner. I changed out everything, cleaned MAF, pulled out & cleaned injectors, cleaned K&N air filter and went to mechanic and had the oil and filter changed. Cleared codes, drove off and still had the hesitation, vibration, no power and the codes came back saying #3 misfire and then later, #8 misfire as well.

WTH is going on???? Any help? Please!!!

 

Any luck on your problem? I have a 2006 with the 5.4 and I have done the same all 8 plugs, 8 cop's, i have changed a few injectors yet I still get misfires. Now when I run injector cleaner or Sea foam in my truck it runs fantastic for about 500 miles, about a full tank and a half then my problem comes back. When i changed the plugs about 2000 miles ago I found a few broken plugs, I now can assume that this caused my passenger side Cat to go bad? Causing a very slight break down at idle, then on the highway under slight load i get a check engine light flash throwing misfire codes, but if I keep her under 60mph in OD she runs fine with still a very slight break down causing the engine to shimmy but no buck. I hooked up to my car trailer this weekend, when i got on the highway and got it up to 65 I instantly got misfires. So if anyone can provide further info that would be great! I know the FPDM's go bad in these trucks, also injectors clog, as well as over time they have back fuel pressure sensors in them. But none of these common problems convince me the problem leads to them due to the truck running great when I run seafoam in the gas tank.

 

hey so far I have the same problem sluggish acceleration and so far I have changed both cats 8 coils 8 plugs fuel filter and it still isnot running right can someone give me the next step

 

I too have this problem. I have read for hours and hours and no one has given an exact to do. I changed plugs and drove for 90 miles with no problem what so ever. I put in a new fuel filter and instantly got the stutter. Now it's way odd because you can feel misfire slightly under any acceleration but it shakes the truck insanely when In overdrive. If I pull the connector on any of the COPS I get horrible vibration at an idle let alone try to drive the darn thing... so it must not be an actual miss but something more subtle? Why does no one have an answer for this? If I find one I WILL come back and WILL post an answer.

 

Wish I did have an answer. 2004 w/4.2 V-6. Misfire #3. Changed plugs, wires and fuel filter. Air intake filter is new. Had the converters smoked and they are good. Right now I am good under normal acceleration, just when I get on it. This truck only has 48k miles on it.

 

A few thoughts for all 3 of you:

Make sure you are applying sound troubleshooting techniques. Just because you're throwing reasonably inexpensive parts (plugs/coils/filters) at the issue doesn't mean you're not throwing parts at it. The rule for good troubleshooting is "change one thing, test" -- if you change more than one thing at a time you won't know which one affected the issue.

Invest in a code reader. A setup using your phone, the Torque Pro app($5), and a $25 bluetooth ODBII reader from Amazon is perfectly fine.

With that in mind... (in some order related to ease of job/least expensive/most likely to be the issue):

1. Plugs - not uncommon to break the new Motorcraft plugs (you're using Motorcraft, right?) on install and end up with another bad plug and the same issue. Get another new plug and change out each one (ONE AT A TIME) and see if there's improvement. Not exactly sure why this happens (though there are theories) but it does.

2. Coils - are you using Motorcraft coils? If not, best to do so. I know they're more expensive than the set of 8 on Amazon for the price of 1, but you'll have better luck. However, before springing for 8 Motorcraft COPS, buy 1 and swap out 1 at a time... check for improvement. (It's surprisingly not uncommon to get a bad coil - brand new part (even Motorcrafts). Happened over the weekend to the guy who sits next to me.

3. Fuel Pump Driver Module (mounted to the frame under the spare tire. $40 or so, 2 screws). Worst part of this job is winding down that spare.

4. Clean/Replace MAF (easy to get to and change, right there on top). CRC sells a spray cleaner if you choose to go that route. Replacement part is around $35 I believe).

5. Clean throttle body. Pretty easy job, but don't be tempted to clean it while it's in the vehicle... remove the part before you clean it, or it will remove your finger(s) before you can count to 10... oh wait, you won't be able to count to 10.

6. Injectors - give 'em a good cleaning. Rigging them up to test can be a bit of a pain, so maybe run some additive through them to free up anything that's sticky.


My guess is that by this point your trucks will be running better.

If not, then it's time for compression testing to see if there's a bad cylinder and then getting into some more in depth stuff.

check out YouTube for FordTechMakuLoco -- he's got amazing videos on many of these issues, and he explains things clearly and thoroughly. He's really been a fantastic help in keeping my truck on the road!

Good luck to both of you (all 3 if LilChris is still listening).

Cheers.

 

Thanks for the input Doc. Hopefully I have managed to get mine to straighten up. After the repairs mentioned, I have put 3 tanks of 100% gas (non-ethanol) through it. Performed much better on the afternoon commute. I think I will also do the fuel pump module and clean that throttle body.

 

I joined just to share my experience and let you know what I have fought so far on my truck. Here are a few details:

2005 F-150 Supercrew 5.4l 3v
173,000 miles
Changed one injector around 65k
Torque converter change around 120k

This year I lost the battle in keeping the truck alive and was facing replacing the head on one side, looked at the cost of doing both and decided to pull the motor and drop in a new one. Got the truck back with new motor installed a few weeks ago. Because of my budget at the time I had the shop swap over the injectors and COPs.

Since getting it back, I have had flashing engine light and code for cylinder 3 misfire at WOT or under load at highway speed. Since I knew we had swapped over some parts that might have been bad I went ahead and replaced all COPs and the injector on 3. Still got a misfire on 3.

We decided to swap plug from 3 to 6. Still misfire on 3. Next we swapped injector from 3 to 6. Still got the misfire on 3. Finally, we swapped the COP on 3 to 6. Still got a misfire on 3.

Thinking it might be a computer issue, we checked continuity of the wiring of cyl 3 back to the PCM. All appeared fine. Yesterday we had the local Ford dealer reflash the PCM. Still getting misfire on cylinder 3.

All that to say, on a new motor there is not too much more that could be causing one cylinder to misfire consistently...at least in my eyes, but this thread has been very revealing.

They are replacing an O2 sensor and doing a blowback test today to see if it is the CAT. I will report back on what we find. I am hopeful that this info might help someone that is seeing a similar issue with their troubleshooting.