Exahust leak / old 02 sensor = bad mpg
Guys, I've been doing a lot of reading on some tuning forums.
One thing I see over and over again is that exhaust leaks cause inaccurate 02 readings. Even very small leaks! The result is often excess fuel consumption and one bank running richer than the other.
So.. if you feel your mpg is down as compaired to where "it used to be"? A thing to check is for exhaust leaks. **especially** at the header to mid-pipe connection. Leaks back by the muffler can effect it.. but not much.
Also, 02 sensors that have more than 60k miles on them will start to get "lazy". Meaning that they work. But they swing from high to low and start to falsly read leaner and leaner which adds fuel.
He who is enslaved to the compass is free to sail the seas