88 Toyota Pickup engine noise

What should the owner do?

Regardless of whether Tom & Ray are right, I can’t suggest strongly enough that a 20-year-old 22R engine have the valve cover removed and a good hard look into the timing chain area. If the driver’s side chain guide is broken, it’s just a matter of time before the chain will rub a hole in the back of the water pump housing on the timing cover, just as if it were a chainsaw. The result is engine oil becoming brown mayonnaise (just like a head gasket failure), the coolant that did this starting serious corrosion on the innards of the engine, and the customer having to fork over relatively serious bucks for a new timing cover, on top of all the timing chain stuff.