2.0 petrol 2001 model since November. throttle body has played up, high/low revs, limp mode etc. the magnet shattered on the rod/bar inside throttle body. Not sure what you call it, but it clearly needs replacing. how/where I can purchase just the rod or do I have to buy the full throttle body? nut on the end of the rod, does that imply you can replace the magnet only?