My 76 bronco is doing exact same thing. The other gauges are fine but oil pressure when you start the engine it just starts climbing about 85 I changed out the sender to a new motor craft today supposed to be the right one for this gauge. same as my 65 mustang When I started the engine up 10,000 miles ago new I put a mechanical gauge on there and it reads about 45 , Subscribe to this I’ll be watching to see what you guys come up with