Subj car's battery goes dead every few weeks; I've cut and taped loose wires that lead nowhere that were in the trunk (I found this instruction on this site, thanks. Also, thought it may be alarm-related, or ignition key related. So I started using new (unused) key for igition, and a tiny fuse thing fell out of it. Didn't know there was a fuse in the key, guess that's why the key has that fat black plastic thingy. Have also tried removing inconsequential fuses one by one, but hasn't helped so far. Any ideas??

Separate issue, my engine's hestitating and seems to be getting worse, what do I need to do to fix that?