Last nite when i was driving i got a check engine light. So today when i got up i took it to autozone to get the free test on it to see what the code was. (mind you the car is driving fine and sounds fine) So they check it and it comes up as a Catalyst Efficiency. I asked them to tell me what does that mean and they said the car is not getting the rite amount of back pressure. What can i do about this? and how do i fix it? Ive had my flowmaster mufflers on since December and i have had my Magnaflow X-Pipe with high flow cats on for about 3 months now. What can I do? whats causing this?

 

I dont think back pressure has anything to do with the code, it is more likely a faulty O2 sensor, take it to a Ford dealer or get a tuner like SCT or Diablo and read the code right.
I had my car running with no cats and straight through mufflers (no backpressure whatsoever)and got no codes.

 

This one is simple, you need to get mils or have the rear o2 sensorsturned off via a custom tune. Any midpipe other than the stock h-pipe will trip thiscode in most cases. Hiflo cats or no cats at all will flow much better than the stock h-pipe setup and the rear 02's only job is to monitor the catalyst efficiency of the stock cats anything else just flows to well and makes the rear o2's think the cats aren't functioning properly. Don't go to the dealer. I would get a cai/tuner from a respected performance shop and they set the tune up for the specific cai and any additional mods you have such as the hi flo catted x-pipe. This is a simple fix.

 

Ok thanks guys!

 

Now i got a reason to buy my intake/tuner package now! lol.....Ive been draggin A** with buying it lol

 

I would buy a complete exhaust system with O/R pype also since the catalysts are the problem lol

 

I am also thinking of that to! ^^^^