I am trying to decide what cats to get to replace my rear cats. Ive narrowed it down to 2 products, both are Magnaflow.They are the 94306 and the 94316 which are identical except for the last one has Air injection. Can someone tell me what Air injection is and which one will work best for my truck? My truck is a 2002 f150 w/ the 5.4, thanks.

 

You do not need anything with air injection. The best cat for your truck is the 94136. It has one O2 bung already installed. install this with the O2 bung downrange of the exhaust flow and reinstall your aft O2 sensor here and you're in business.

 

x2.

 

Sweet thanks guys.

 

Also will these still work if i gut my front cats?

 

^ DO NOT GUT. Replace all 4 stock cats with a pair of maggie cats!

 

And I won't have to worry about a CEL if I do so? I really want to do it right this time and not have any problems.

 

x3 on what Galaxy advised, and x2 on not gutting a whole catalyst. Big static pressure loss with a big open cat, worse than a chambered muffler.

The two Magnaflow cats replacing 4 will not trigger a CEL as long as your installer does the work correctly, meaning no chitty welds that leak ( remove the downpipes and install cats in place fully tig welded ) and mounts the sensors correctly anywhere from the 10 to 2 o-clock positions ontop of the pipe, without touching the sensor with a finger tip.

 

Right there is a reputable shop about 15 min away ill be taking it to. im gonna get all the parts i need and It wont cost me an arm and a leg to install