ok so i have a 2000 f150 4.6 V8. When i push the brakes the oil & Coolant lights illuminate and the oil pressure gauge drops dead for about 3 seconds then it goes back to normal and light go off. There is no difference in performance or idle or change in other light (headlights, cluster, interior, radio etc.) and it only does it when i apply brakes. Its not happening in park only drive. (havent tested reverse) What could be causing this?

 

Bad ground somewhere. Try the grounding stud behind the driver's side kick panel.