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 catalytic converter is plugged.
2) Reinstall Bank 2 lower and then uninstall Bank 2 upper (radiator) to determine if Bank 2 precatalytic converter is plugged.
3) Reinstall Bank 2 upper and then uninstall Bank 1 upper (hardest one, close to firewall) to determine if Bank 1 precatalytic converter is plugged.
4) 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).
What you are doing is to give the exhaust an outlet. If it performance improves with the O2 sensor removed, you know that is where the Catalytic Converter is plugged. Battery needs to be disconnected before uninstalling and installing O2 sensors. In addition, you need to make sure you have some sort of heat shield where the hot exhaust is coming out of the open O2 sensor hole. The hot exhaust could melt wires and rubber hoses near it. Victor Muffler Repair Kits has some of the muffler shields. Do not drive for more than a few minutes.
1) Uninstall Bank 2 lower (radiator side) to determine if main catalytic converter is plugged.
2) Reinstall Bank 2 lower and then uninstall Bank 2 upper (radiator) to determine if Bank 2 precatalytic converter is plugged.
3) Reinstall Bank 2 upper and then uninstall Bank 1 upper (hardest one, close to firewall) to determine if Bank 1 precatalytic converter is plugged.
4) 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).
What you are doing is to give the exhaust an outlet. If it performance improves with the O2 sensor removed, you know that is where the Catalytic Converter is plugged. Battery needs to be disconnected before uninstalling and installing O2 sensors. In addition, you need to make sure you have some sort of heat shield where the hot exhaust is coming out of the open O2 sensor hole. The hot exhaust could melt wires and rubber hoses near it. Victor Muffler Repair Kits has some of the muffler shields. Do not drive for more than a few minutes.
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