After changing my oil yesterday I noticed something that never happened before. I've floored the throttle in my truck many times for accelerating and never noticed the pressure change. After yesterday if I floor it the oil pressure drops. It is at about 5/8 up until about 3 grand then it will continue to drop until it shifts. It has gone down below 1/2. One time the light came on. I believe this changes the theory of our trucks only having an on/off type oil pressure sensor. The oil is in the correct range for level. The only thing I can think of for this happening in my pump decided to suck the pan dry(well, maybe not dry but close) all of a sudden.

 

I would love to more details. Did you change viscosity or brands. Did you go synthetic form dino. What motor and how many miles???? Sooo many questions!!

 

What year truck is this? The 97+ have a dummy oil pressure meter.

 

And that is why a lot of the people on this board have installed a mechanical gauge this is REAL, and changes with RPMs. Check my sig for the link on how-to.