Repair water fill-up on Whirlpool Stylemaster rev B?

Whirlpool Stylemaster 4213632 rev B -- On the water fillup on the "2nd rinse cycle" ONLY, the water only comes out as a trickle (vs. full stream everywhere else) and what sounds like a pump makes a noise at the beginning of the rinse. I have tested all wash cycles and the extra rinse cycle, and all water temp combo's. It does this consistently on 2nd rinse and extra rinse cycles. It does this occasionally on other water fillups. And just now, it started out as a trickle on the 1st rinse on the gentle wash cycle and after several minutes (3-4) started a full stream on the fillup. To me, this problem acts like a possible short related to a water pump.

This problem started last week. I've checked all water hose connections, all wash cycles, and all water temps. I've called my usual appliance tech, who have retired, and he was baffled. My work around has been manually adding water from the sink.

This is a top loader purchased in 1993, and is only my 3rd problem in 30 years -- so I DO NOT want to replace it.