Originally posted by Contour_dave:
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4) Somewhere on the board I saw that if you disconnect the upper 02 sensor and it runs better the problem is ????something????, any help here?
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Plugged exhaust test.
For the Duratec, a good cheap way is to remove the O2 sensors, in this order (and see if the performance improves).

1) Uninstall Bank 2 lower (radiator side) to determine if main cat is plugged,
2) Reinstall Bank 2 lower and then uninstall Bank 2 upper (radiator) to determine if Bank 2 precat is plugged,
3) Reinstall Bank 2 upper and then uninstall Bank 1 upper (hardest one, close to firewall) to determine if bank 1 precat is plugged.

You don't need to mess with bank 1 lower as bank 2 lower will also be a test of that issue too (if it is an issue). Battery needs to be disconnected before uninstalling and installing O2 sensors. Good luck.

"Always do the cheap and easy ones first." 1996 V6 ATX 96K miles