I just purchased a 2014 silverado, put the first 1k miles on her and decided i wanted to drain the FF and filter so i replaced it with a Fram Ultra, not sure if this is the filter or not but the oil pressure always read 40psi while driving except when passing it went to 50 or so, with the ultra on just cruising at 55mph the oil pressure would go to 60-40-60psi for about a 1/4 mile, it did this almost everyday. I started getting real nervous so tonight i changed it out for a oem ac delco. I just got back from a 50 miles ride and the pressure only went to 50psi while merging on the interstate at almost wot. Could the fram had a problem? I also had valvoline synthetic in and drained that for mobil 1, thank god i did, the valvoline is the first oil i ever put in a container and saw so much foam, i always do my own maintenace and never saw any of these weird things. Any hints on what could have been going on? Thanks