04actionfx4

I own a 2004 F150 5.4 and was wondering could I run two cats instead for four like the 06s and up? Would I need to buy two new replacement cats made for the newer trucks or just delete two of mine and would I need a tune to make it run right??

FordSilly

I would think you would just need a tune to keep cel from triggering.

Storm Chasing Ford

If you take out the pre-cats (the 2 smaller cats closest to the engine), it shouldn't throw a CEL. The only ones that will throw a CEL if removed are the 2 bigger cats with the O2 sensors.

04actionfx4

Yeah I have heard about some people removing the two smaller cats but they all seemed to have programmers and/or tuners so i wasnt sure how it would affect my stock system

04actionfx4

I guess one of my main questions or concerns was the placement of the o2 sensors. There is one before the small cat one each side and one in front of the bigger cats. If I were to remove the smaller two would i need to keep the o2s in the same places which would put both before the cats??

Storm Chasing Ford

The O2 sensors should only be on each of the bigger rear cats from what I've heard.

04actionfx4

I looked under my truck and there is none behind the big cats. One in front of the smaller cats one each side and one between the cats on each side. If they were only on each side of the bigger cats I would just go ahead and remove the first smaller ones and see what happens

FordSilly

Which ever set has no 02 sensors behind you can remove with no cel

Storm Chasing Ford

Couldn't tell ya much else except that I'd reccommend a professional do it, cause if you throw a CEL for too long, it could change your air-fuel ratio and make your engine run a lot worse from trying to fix itself.

Especial86

iTrader: (1)

You can cut the rear cats off on the 04 model no problem...




It should look like this.... The 2 front cats closest to the engine remain.