Toyota Repair: 88 Cressida wont start from time to time, oil pressure sending unit, low oil pressure

Question
Hi, Ted. Great to find that you are helping so many guys with your expertise.
I just bought a 1988 Cressida GLX from a dealer, 3L engine, automatic. Everything seems fine but it won't start from time to time. No sound, no click at all. But sometimes when I get back to it in couple of hours, it starts again. The battery is new. Another thing is that when the key is turned, sometimes there is a warning message of Low Oil Pressure. But this always disappears on driving. I am totally new about cars. Look forward to your suggestions. Many thanks.  

Answer
There may be a problem with the neutral start switch, check to see that the bolts holding the switch on are tight, check the connector for any corrosion on the pins, try replacing the switch if there are no obvious problems.
Is the low pressure light on when the engine is running and how long does it stay on, it may be just a matter of replacing the oil pressure sending unit.