had the same issue on my new 406 had a "F---" on it and after second start oil pressure was 20 psi and stayed there. when i first started it it was 65 psi. put a napa 1060 on it went right back to 65. thanks for the comments about "F---" I WILL NEVER USE ONE AGAIN AND I AM TELLING EVERYONE I RACE WITH AND KNOW ABOUT THERE PROBLEMS
FRAM
F-FREQUENT
R-REBUILD'S
A-AND
M-MONEY