I have an 05 6.0. I did the blue spring mod a few years back. Checked fuel pressure today and key on engine off come up to 51, and also idled at 51. A couple blips of the throttle and it come down to 49. Does anyone know if the blue spring gets weak? Maybe I just need another spring. I wouldn't think it would be the pump with the KOEO showing 51 with no fuel even being consumed, but who knows.