I have a 04 FX4 5.4 and am having trouble getting true dual exhaust installed. I have been to 3 different muffler shops and they have refused to do it because they said it would screw up the computer and the O2 sensors! Surely that can't be it, or is it true?

 

if they do it from behind the cats it really shouldn't... but i guess it can at the same time. IMHO you should plan how you want it set up from the cats back. LEGALLY you can't remove the cats, so that is one curve you need to get past. I think there is a Y pipe that brings both sets of cats together, what im going to do with mine is split that Y and dual it off of it.

 

I was thinking about splitting at the Y also and just couldn't understand if it is behind the cats why should it matter?

 

It doesn't matter. The shop is just too lazy to put the dedicated time and effort into fabricating an entire system.

 

^ exactly!

 

X3

i have true duals with no problems.

 

I have true duals on my 04 lariat with no problems

 

Keep shopping around, you will find one that wants to do more than just install a muffler or tail pipe. I had to hit several before I found one that wanted my business.

 

Well from what I've read, it will mess with the O2 sensors by running true duals without the cats. But that's easily fixed with a good programmer like SCT X3 or a Gryphon with a custom tune from a good reputable tuner

 

^ Now you got it!

 

I finally found a muffler shop to convert my truck over to true duals for 350, includes 2.25 pipes and turbo muffles....