I have a 2001 f150 5.4l screw and i think my cats are going bad. It has started to get that stinky smell. would it hurt to only run two cats and if it wouldnt what would someone suggest. I really need some input on this. is it possible to do and not set the check engine light off. my truck has 152000 miles and it seems to be losing power. I have done plugs, k&n air filter, changed all my fluids over to royal purple. i also have a fresh trans. Need advise please

 

Use the search button at the top of the forum in the exhaust page. I see you are new to the site. On this site searching will become your best friend. I'm not sure about your question though. I know I've seen guys on here run just two, assuming you have four. You may want to specify a little to let the guys like 88, Darren, and avfrog who know their stuff help you. Such as which ones are you going to take out or what is your exhaust setup whether it's stock or not. Just suggestions. Welcome brother truck dude

 

You can scrap all 4 for 2 hi-flow models from Magnaflow, universal fits. #94306, & the louder model #94106 cats for replacement. Have the rear O2 sensors remounted after the new cats, no CEL.

 

Sorry for not explaining what kinda system i have. I have four factory cats and nothing but pipes after that. I tryed flow master muffler but it wasnt any louder than stock. I have been looking online and what i have seen is complete sides. I know from searching on here that if you remove the front cats the truck will run like crap. I am fixing to have to do something but just not sure what to do.

 

i have the same year truck/motor as you and i took off the rear 2 cats about 20k miles ago and havent had a CEL yet. it runs just fine.

 

That's incorrect and I doubt you got that info from here. You can drop the exhaust down and gut the front cats or remove the rears. Most just remove the rears and replace with a 2.5" pipe.

As long as it's tight, you shouldn't get a cell.

Removing all 4 cats isn't advised without tuning. Unless your replacing w/high flows. The factory tune won't fly without converters. It more-less will fall on it's face. So you need a set, just not all 4.