I did an unconventional experiment when I accidentally broke my exhaust nuts & couldn't screw the pipe on. This led me to drive 360 miles without a midpipe, cat & muffler.
The result was the best gas mileage ever. I drove 330 miles before the gas light came on. My previous best was 315.
I put on a highflow cat but took it off because it had a severe drop in mileage. But when I take the whole thing off my mileage goes up..hmm so now its time to tamper with the 2nd O2 sensor.
Its something I don't want to duplicate again but it led me to do to 2 different tests to try out.
The problem with my car is if u lean the fuel too much the 2nd O2 sensor picks it up because theres no gas to burn in the cat. Its all got burned in the more efficient A/F ratio. The 2nd sensor mimics the first sensor & inefficient CAT cel (p0420) is given robbing mileage again
1. O2 Simulator - Trick the 2nd O2 sensor to thinking everything is normal.
http://www.mkiv.com/techarticles/oxy...sor_simulator/
2. O2 Sensor Deadzone - A O2 Sensor that isn't in direct exhaust airflow fluctuates different than the first one in direct airflow.
http://www.k-series.com/forum/showthread.php?t=8833
Im going with the $5 option 2 mod first to see if it gives me more control of the air fuel ration w/o making the CAT mad.
Anyone else dont similar tests?
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