I've noticed absolutely ridiculous gas mileage from the test pipe-back exhaust install. I just reset my ecu (3rd time now) and the gas mileage seems to be normal. I don't mind resetting the ecu every 2 or 3 days (unhook -'ve on battery) if it will restore normal gas mileage, but does it restore gas mileage (ie. does the cel begin the gas guzzling)???
If i take out the O2 sensor, and wrap in in tin foil (do i cover the whole thing??), do I just put a screw back into the O2 bung to close it??? lots of questions, and I have used the search function, I just need some small technicalities sorted out. thanks.

 

No - the ECU makes ignition timing changes, etc in real time based on readings from your 02 and other sensors. Resetting won't effect your mileage.

You should look into an 02 Simulator.

 

really......well, I do have a universal carsound cat at home, but i'm waiting to get my header on before a shop welds it in. Since the ecu reset yesterday, my car has went 50 kms which would normally provide a noticable drop on my gas gauge (yes, my mileage is that crappy), but my gas gauge is still very full.....I don't know.....Thanks for the response, I know these topics are covered fairly often (although I could not find exact answers to my questions).