Originally Posted by
oledoc2u
you have to back track with what was done to make it right. You changed injectors back to stock. Did the old modified injectors failing slobber enough fuel to ruin the cats? Did something fail with the new install of the new stock injectors? Could a sensor have failed like the AIT sensor, failing meaning it broke a tab, allowing it to leak. I had this happen and it ran like crap. You have to look backwards and retrace their steps.
The only "cats" that are on there are the 200-cell race cats from the prototype NW downpipes. The O-2 sensors are just in the J-tubes, the race cats are downstream of the sensors. So, really the O-2 sensors aren't reading anything...
I offered to remove the downpipes and replace them with the factory 4-cat setup, but he declined, wanting to keep the option to run cutouts.
When I sold him the car I told him I'd throw in the stock pipes, as they are of no use to me. To date, we haven't met up to make the exchange.