Apologies in advance because I have seen similar issues in various threads, but have not seen anyone with an on-again/off-again problem that I am having.

1992 Accord LX sedan

For a year+ now the driver's window works periodically but with some grinding. When it does work it catches at a couple points and I have to manually pull/push the window past these points to get it up or down. It makes the grinding noise only when it is stuck at these points.

When its not working, it will not operate at all for a day to a week or more and then for no apparent reason start working again for awhile. In this case, there is no window movement and no grinding. The motor (or regulator or something inside the door, definitely independent of the switch) will click a half second after hitting the switch, but that is all.

Fortunately when it has been completely non-functional it has been stuck closed or almost closed. It is now stuck all the way down and has inspired me to fix it finally.

Since it has been totally non-functional today, I have checked the fuses and tested all wiring to the switch and regulator/motor. All seem to be fine and it is definitely drawing some juice when I first hit the switch. Window seems to be aligned properly on its guides and everything seems to be clean enough with minimal dust/debris build up.

What could cause this problem to happen only periodically and what causes the grinding at only a few points in the motion? Any chance of fixing this without replacing the motor and/or regulator?