hi all i have a 51 plate duratec mondeo recently i had the fuel pump replaced during which the dope at the garage dropped my exhaust. After getting my car back the engine management light came on took it straight back to be told bank 1 and 2 sensors had failed they deny it was them after getting the post cat sensor of easily enough tried the pre cat STUCK solid any help or ideas would be great before i give in and replace the exhaust manifold.

Apply heat to it with a gas torch and that should break the seal a little and loosen it off.
Wait until its cooled and it should come out with care.
Just make sure you don't catch anything on fire.

As already said you will need to apply a lot of heat. If it is stuck really bad you will probably need oxy acetylene to get it red hot