I recently bought a 06 f150 with 136k miles, and I changed the plugs due to concern that they hadn't been replaced, I ran some lucas injector cleaner through it and I changed the plugs and they had autolites in it and I put motorcraft in. On the rear passenger plug (#4 I believe) was loose and black and the coil boot was disscolored(the coil had been replaced). I installed a new coil to replace it since I was in the area. So now after 200 miles I have a po420 (I'm not certain its the cat but could be). I'm now thinking maybe I had a stuck injector. I put some seafoam in the tank last night at a suggestion from a guy who had same code and said he runs seafoam through his f150 and it goes away. My question is could my plug being black be from a leaking injector? I haven't ohmed any out yet or pulled any. They were loud when I bought the truck but I believe the lucas has quited them down. I also have a pic of my plugs in order if it helps.

I'm at work so If more info is needed I will post later.

 

According to some previous posts on this forum seafoam isn't good for the cats. Use Chevron techron or Gumout with Regane

 

Welcome!

 

I was at work while I wrote that, so I was trying to get it done incognito.

 

I moved your thread to the V8 forum. You should get more help here.

 

Skyler,
Let me try to answer some of your questions:
Yes, a black spark plug is indication of an over rich mixture, a leaky injector MAY cause this, depending upon how it leaks, spray pattern, etc... However keep in mind a plug that has not been firing will usually be cold, wet and black.

Taking ohm readings on your injectors will not tell if you one is leaking, only if it has electrical issues, like a short, or an open. A leaky injector is very difficult to diagnose, unless it is a gross leak.

Sea Foam has a love/hate relationship with folks, especially on this site. Folks either love it, or hate it. I have seen it work wonders first hand, though.

IMHO Lucas products are great. I have used them with very good results, including their fuel cleaners. However some think you can only follow what they have heard works.

If you can upload pictures of your situation, they are always a big help.

Oh yeah, lastly these engines seem to have loud injectors anyways. Without hearing yours first hand it is tough to determine if they are "too" loud. Although if the noise is too loud, it may not be injectors and may be more inline with a phaser knock. Pay close attention to the noise and see if you can find out more about it.

Hope this helps get you going.

 

Thanks for the reply. I uploaded a pic on my album. The plug wasn't wet, it just had a lot of black carbon buildup, it also didn't have a motorcraft cop on it but it does now. For some reasonthat was the only one not motorcraft. As far as the ticking sound, its deffenitly not the phasers and it is the injectors. I took a homemade stethoscope and and placed on each injector and on the front of engine where the phasers are located and on the Solenoids and I confirmed that the only noise present were at the injectors. I was also albe to pinpoint the loud injectors as the others were quieter. I personally do not like seafoam as I've had problems with it on 2 vehicles but when I described my problem code to another owner he said his did the same and he would run seafoam through his when that code popped up.

After saying that, the seafoam actually made the injectors loud again. I'm not sure if my cat/cats have failed but I do know after replacing my plugs at the very first start up I had minor backfire. About 5 times as I reved the engine just to see if it would clear. It has cleared and hasn't done it since. I can't run it on a computer at a shop now as I erased the code. So now I sit here like a bird in the wilderness waiting for it to pop up again.

So my question now is should it turn out to be that the cat/cats have failed should I have new ones welded on or just buy the whole sections. I'm a big proponent of factory everything and am wondering if fords are sensitive to aftermarket cats?

I'm very mechanically inclined so I do all work myself except welding as I don't have one.

 

I figured out how to post the pic here. Also if you look at #7 (I think its the one on right side 1 fron the back) it has a little black carbon on it below threads.

 

It also takes 10.2 seconds to get to 60mph which I'm not racing the truck but I thought it was a little slow, my 05 z71 I traded in for this truck would haul hinney but it was also a h.o. engine. This f150 has a slight engine shake and I think that most do but I could be wrong. Other than my concrens I love the truck even though I'm a huge chevy fan and hate Ford's. But after 2 silverados drop oil pressure back to back I decided to give ford another try.... I had a 04 f250 with a 6.0 ........my gosh that was the worst engine.....but I'm hoping this truck is a good one, it sure rides better and looks better, but hey I didn't leave chevy, chevy left me!