Thanks for the education!

BOD off is still the same. It might have given a little more torque, or that might just have been wishful thinking on my part.

I have few capacitors on the board, just the ones specified. By now, I'm pretty sure that the PIC is doing the right thing, and that the problem lies with the motor driving L293D circuitry. So I went looking for other drive circuits, and found another which was just like the one I had built!

So everything seems to be right. The problem is, it isn't. Does anyone think it would be safe to up the voltage beyong 6v? The battery pack that came originally with the motors is 6v, and the coil windings are around 18ohm, suggesting 0.3 Amp.