OK, Less than 15 months ago I replaced the pressure tank (now a 42" fiberglass model); pressure switch, submerged well pump, and standpipe (now black poly pipe). My 120' well had water at 45' - clear. Cold, and plenty. Today my pressure will suddenly slow from 58 to 40, then drop to zero instantly. While at zero, the pressure switch trips constantly. After 40-50 seconds, pressure jumps to 58 and flows for 5-7 minutes.

It is the switch? I know the tank is not waterlogged (light as a feather), and the pump runs like new when its on, as I can hear it easily blasting water up and into the house feed. What gives?? Help! Wife has dirty dishes!

I just replaced my pressure switch yesterday and now I'm having a similar problem as you. After talking with a plumber he said the little nipple is clogged up from all the sediment. The water pressure isn't getting to the switch fast enough since it is clogged so the water eventually runs out and when the water finally gets to the switch it will turn it back on and you get your water back. Hopefully you can just clean it and be done with it.

The "nipple" DK's referring to is usually an small copper tube leading from the pump to the control box. Check and clear ant let ne know if that fixed your problem.
Good luck, Tom