I have a 94 Prelude, when I try to shift it grinds, but not all the time, if the car sits for a few days its good for several miles then I can't shift gears again. Someone told me that there is a switch or sensor that can go bad. Or do I need a new clutch or tranny?

Any help would be greatful.

 

If you've never changed the clutch since you've owned the car, I am willing to bet the clutch needs to be replaced.

The first thing I would do is change the tranny fluid if you are not in the position to get the clutch replaced.

 

Change your gear oil with honda manual transmission fluid. Also honda released a TSB (Tech Service Bulletin) on prelude and accord manual trannys for 5th gear upshift grinding and bent shift forks.