BMW Service advisor telephoned this afternoon to say that they would like to replace the return valve to the gas tank. $650.00. I asked if this is the pressure damping vent valve allowing manifold vacuum into the return line? Advisor said he did not know. I asked to have the mechanic contact me to discuss. They made sure to tell me that this is the starting point for identifying the problem which tells me, or at least I hope that it tells me, the HPFP's may not be the problem. Fingers crossed.
If you look at the earlier post in this thread from Gadget760Li you will see why I was asking the question.
By the way, I live in Greenville, SC so you can look up who the dealer is in this area.