Bosch plus 4. I must have missed that.

 

Not very many people get away with using Bosch plugs in your model year. I'm surprised you haven't picked up on that. Bosch makes great products , don't get me wrong. BUT, your motor will go buggy on them and will eventually get the random and multiple misfire disease. To put it simply, you need to get those plugs out of there and replace with Motorcraft Platinums OEM. That's a definite problem, trust me , I know...I've seen this problem many times..

 

Yes I know I have read here several times that they are crap for these trucks. I'm going to change the two cylinders out with some autolite's and see how it does. Going to order up a set of nkg's or denso's. I'll change them out tomorrow afternoon work and I will report back.

 

No, not Autolite's lol - Listen I know Autolite makes Motorcraft plugs and hell, they even look identical.. Guess what , there different heat ranges and these motors are picky. I tried to run them Autolites once. I had one cylinder misfiring on the way to work the next day and mutiple misfire's on the way home, barley made it back. I put my old Motorcrafts back in the truck temporarily until I could get back to the store(major PITA!!)..

Look @ the Autolites in the pic below. I pulled them out after I had the problems --- They heated up so much that they turned colors lol....




Your definitely on the right track - NKG's , Iradiums, Motorcraft's .. Those are the plugs for these Modular Motors.

However , if your having misfire issues , I would stick with the OEM fail-safe Motorcrafts Platinum's to eliminate "plugs" as being a part of the problem.

Good Luck Flareside..

 

Pulled plug 3 out, and almost crapped myself the plug was destroyed!!! I popped I new plug in 1 and 3 and the motor ran alot beter so I go into town to do some errands and bam the truck is running like crap again with a #3 miss. Get home I pull the plug and it looks fine.

 

P.S. I will post pics of the plug that is messed up soon. Looks like something almost hit it

 

Check this sucker out this is number 3 cylinder!!!!

 

i'm having this exact same code/problem with my 2004 5.4L.... exactly as describe above, only misfiring under load on the highway. if the code is showing a LEAN condition, shouldn't that mean that there is a lack of fuel rather than dumping unburned fuel through the cylinder? i'm struggling with the used dealer where i bought the truck from (1 week ago) because they are claiming there is nothing wrong with it. i'll get them to pull plugs #1 and #3 just to see what is there, hope my plugs don't look as aweful as your's flareside...

 

I'm think I'm going to get the injectors and fuelrails flushed that is the only problem that I can possibly see left

 

Holey Crap!!! What kind of plugs are those ??? What did you do to your motor Flareside ?? LOL , kidding ... What do those plugs look like new ? Do they have 4 legs - from thread perimiter to the electrode??

That's the ugliest plug I ever seen

 

Your on the right track - Your getting back a lean condition because the O2's read after the burn. Misfire = NO burn. Your sensors report it as a lean condition..Lean = <(less than) . The trucks only firing on seven instead of eight..

As far as RAW fuel goes - You determine the injector is not at fault first - purchase a noid light at your local auto supply (there like 5 bucks) , make sure your injectors are pulsing correctly. If it is , The prob is with the COP, Coil Pack, boots or wires.

You need to fix a misfire ASAP - all that raw fule could detenate inside your Cats and destroy them....

 

Bosch +4 they are gapped at .054

 

If you know what cylinder is misfiring - I suggest you unplug the injector until fixed ..

 

Alrighty I'm going to drop it off at my buddies uncle's garage so they can check it out.

 

i did some searching around and from the pics i found it looks like you have a detonation problem... so i'd look for not getting enough fuel. i guess that makes sense with the code you are getting. i'm picking my truck up later today, i'll be sure to ask if they read the plugs they changed. i'm sure that is all they did as well (change the plugs) so i'm looking forward to having the same problem come back.

check these out:
http://www.dansmc.com/Spark_Plugs/Sp...s_catalog.html

click on "reading plugs" on the left.
http://www.nightrider.com/biketech/spkplghnbook.htm#We