Car battery is almost new, as is the alternator, and all appears to be
functioning properly in the electrical system.  I've also now determined
that, if I do so at a time when the keyless system IS working properly, I
can reprogram it using both transmitters, and that, immediately after the
reprogramming is completed, the keyless system will respond properly to both
transmitters.  However, I can return 20 minutes later, start pushing buttons
on the transmitters, and nothing will happen, and thereafter it's back to
intermittent functioning/malfunctioning.  I'm beginning to think the problem
lies in the receiver unit.  Any other suggestions would be appreciated!
Thanks again, PE