If you see your brake coming on when you press the throttle, or throttle when you press brake, then the pots are loose in their holder, a common problem.
What is happening is the pot is loose and with the wires for both pots all tangled up inbetween the pedals, you are moving the other pot through the tangled wires.
There is a little nub ball on the bottom of the pot that sits in a slot on the base of the pedals. I originally tried to wedge a piece of folded up paper in there to tighten them up. That was a long time ago. Shortly after, I read someone here used "blue goo" or some type of silicon gasket stuff, or even caulking would probably work, to try to hold the pot in better. My little nub on the pot has since broken off, which I used a cheap JBWeld product to make a new tab to hold it in. That worked for a while. Recently I just superglued the sucker on there.
Somewhere around here is a thread on Momo/DFP pedals that lists a part number from some site that actually sells the Momo/DFP replacement pots. The product they list is actually called "Momo pedal potentiometers" or something like that. I no longer have the link, nor do I remember the exact company or what thread here it was in.
Scratch that, here's the link, Momo Force and Momo Racing Force repair kits (2 separate kits). The Momo Racing Force kit would be the same as the DFP since they are identical pedals:
http://us.digikey.com/scripts/ ... ;Site=US&Cat=33882652