Oil Pressure Gauge Acting Very STRANGE!!!

[scooter8448]

I have a 1994 2dr GMC Yukon 4x4 5.7 V8. The oil pressure gauge would normally run about 40psi when driving down the road and about 10psi on idle at a stop light. Well about a week ago it started going past the high 80psi reading to a complete 3 o'clock position far from the reading when you accelerate (not hard accelerating either) and when you let off the gas it would go to about 15psi. When you take off from a stop it would go back to the 3 o'clock position almost instantly. There are no lights lit up on the dash and the motor still runs like a champ. The oil pressure switch was changed out about 25,000 miles ago for a completely different reason. Any ideas???

[1997SierraSLT]

first guess would be failing oil pressure switch or a bad electrical connection at the switch.