Originally posted by azhari
Great to hear you got your fuel mileage back (well, most of it if not all!).
If you run OK open loop and crappy closed loop, I guess now you ONLY have to deal with an electric issue!
Is your car running OK in open loop with the existing cat?
While not official, I think my mileage is back up around 22-23 mpg. It's starting to get cool at night so I have to deal with the cold start issue of running open loop. And yes, when the engine is warm it runs fine in open loop.