|
A common source of bad mileage is an air leak in the exhaust close to the O2 sensors. The sensor detects the extra O2 and the ecu thinks the afr is lean. The ecu then tries to compensate by adding fuel, resulting in a rich afr and crappy gas mileage.
So it is very possible that the y-pipe has a bad O2 sensor fitting that leaks air, or a warped flange, but it may also be true that the problem may be at the header mounting flange, or it may just be that you need a new crush gasket between the y-pipe and the header. Or it may just be that you need new O2 sensors.
At any rate, you can get an aftermarket y-pipe installed for much less than $900.
|