I will check the return line, I too think that the pressure of 9-12 PSI out of the mechanical pump is too high...

I know there isn't a kink up front, but that deosn't mean there isn't one forming in the rear..I will have to get back there and look...

As far as the sock, good question. The tank was replaced the same time te lines were, but I can't remember if the guy who did the work replaced the sender assembly, I am leaning towards he didn't. I would guess at that time (and with how much he charged me for doing all of the work) he would have made sure the sock was clean, but that doesn't mean it is now, although it has only ever had good quality super unleaded. Also, it doesn't mean the thing couldn't have fallen apart somewhat...but since the tank is 3/4 full right now, there isn't an easy way to check...