I'm having an odd charging problem w my 99 Neon that even has my
mechanic stumped. The car has 121,000 miles on it and needs to be
retired soon, so I'm trying to find out if this is worth messing with
or if I should just give up.

With increasing frequency, the battery/alternator light has been
coming on lately. When it's on, the engine races when I stop. One time
the light was on and all my dash lights and headlights slowly dimmed
and eventually my gauges shut down, too. Then, everything came back on
and started working fine for no apparent reason. My mechanic has
checked everything -- when the problem is happening and the car is
running -- and can't find any explanation. The system is charging
properly. His solution is to simply restart it, but I sometimes have
to try that tactic multiple times before I finally get the car started
w/o that pesky light and revving issue.

I'd appreciate any suggestions you might have.