TPS Set Up & Testing?

[Deezull]

Hey guys, I think my TPS has been messed with before I got the car & it is giving me troubles, all of the symptoms of a TPS fault.

What is the best way to test this? I know I use a mulitmeter for this but I would like to know what readings it should be giving at Closed throttle & Open Throttle, and also which pins to put the multimeter on to ensure I make no mistakes if I need to make an adjustment!

It is a 2005 Subaru Impreza GX Sport 2.0 NON turbo

Thanks guys, all help much appreciated!