just had a new starter put in by my mechanic. yesterday, i wake up and the battery's completely dead. jump it... and the car starts automatically with no key inserted. i can't turn the car off so i intentionally stall. then, i find if i engage the clutch, the car will start. this happen to anybody? i'm guessing it's a wire short but could it have to do with the interlock switch?

 

Well, the starter needs the clutch/interlock switch in order to close the loop, but that alone isn't enough to start the car.

The EGI relay must be on for anything to work or the car won't fire.

If the ignition had a short, that would have these symptoms except the starter would continue to spin even after the car started.

Something related to that, I bet.

-Edit-

It just occured to me that releasing the clutch after the car stared will stop the starter.

Try disconnecting the starter and see if any of the other car devices work without the keys.

 

Maybe take it back to your mechanic? You shouldn't have to be fixing his work, if you paid him to install a starter, it should work properly when he gives you the car back.