Whats up, So about 2 weeks ago I replaced my spark plugs and coils. My truck was running fine for about a week and all of a sudden It starts to sputter out, when I floor it. But only when I floor it. It runs fine if I'm not hard on it. I'm not getting any codes. I changed the fuel filter, cleaned the throttle body and air filter. Do you think I got some bad coils that are just kind of cutting out? They are after market.

 

No codes...it's hard to say what's going on...re-check your connections to the plugs...are they aftermarket plugs also ??

 

Yes they are. This is what I got. ( NEW DRAGON FIRE PERFORMANCE IGNITION COIL ON PLUG COP) and autolite plugs

 

Think it could be a bad fuel injector???????????

 

make sure your plugs are tight. sometimes they will loosen, also did the new COPs come with new boots?

 

Aftermarket plugs are the absolute worst for the '04 model. I have an 04 XLT and put aftermarket plugs in there and had the same problems as your describing along with the smell of fuel through the vents. Needless to say those plugs ruined my engine and needless to say my 04 now had a new engine with the ford recommended motorcraft plugs

 

How did plugs ruin your motor?

 

Ya they did come with new boots, but I did not like the way they fit on there. So I used the old ones. And I have been smelling fuel every once an in awhile, not all the time. How did that mess up your motor fordf150man???

 

Even though the plugs were to ford specs the plugs cause gas to get into the engine which in turn causes cam phaser issues and cylinder 3 seized

 

I am experiencing a Stutter, or Shudder when in the low part of the gear, like when accelerating slightly up a small hill or on a flat when the truck is at about 75km/hr and 1100rpm. Its like im hitting bumps. I received a CEL for P0430 Catalyst efficiency below threshold(bank 2). Could this be caused from COP/Plugs that are no good, or could the sputter/stutter/shudder be caused from the bad cat?
I would love some insight on this, as its quite a bit of money trying to chase a problem I have never experienced before.
Thanks in advance, and PM me if you want.