[Grail05]

Originally Posted by Singletrack

My fabspeed setup with extenders has not thrown a SES in forever...haven't kept that close an eye on mileage - but has to be up to 7-10k miles at this point. The fabspeed extenders do not have an abrupt 90deg turn either...it is gradual.

Mechanical fixes can work if done properly. All the ECM is doing, with regard to the cat inefficiency DTC, is comparing the signal from the primary O2 to the secondary O2. It is looking for a specific change to indicate that the cat is working properly. So if you design, and test the extender properly, it will work. If you just throw on an extender you bought randomly, that was not designed for the setup, then no it won't work...or at least not for long.

Likewise, since the rear O2's are rarely in the exact same place on every x-pipe, there is very little chance that a standard mechanical fix will work across the board.

Bro dont u have a HFC?