Thank you for chiming in! Sorry if I wasn't too clear in my first post. Before I suspected a problem with the jet pump, I was suspicious of the senders based on the PO's comment that the gauge was off. So, I pulled both senders partially out of the tank and moved them through the full range of motion, while watching the cluster test and measuring the voltage. They worked as expected. The next time I filled up, the gauge did not go to full. After just confirming the senders were ok I was baffled. So, I open the left side tank again and found the float stuck as the gauge went to full when I re-seated the driver's side sender. Thinking I just solved the problem, I happily went through most of the next tank when I checked the cluster test again and found the right side showing near-empty (a few liters) and the left side around 37 liters. Doesn't this clearly indicate that the sucking pump isn't working as the right side should be mostly full while the left side gradually goes down (when the tank is say around 1/2)? I'll need to do some more checking with the cluster test and check the phase you mentioned. I haven't tempted fate by running out of fuel yet, but with the cluster test only showing a couple liters in the right side, I suspect it is going to run out. Further, maybe the pump is wearing out quicker as it spends most of it's time running in a near-empty tank.

I just got the vehicle and have only put a few hundred miles on it so far. I'm trying to be cautious about throwing money at it as there are no shortage of X5 issues that can empty the pocket book. I'm happy tooling around the X5 and learning more about it, but I'm being frugal and only fixing what needs it. It's not my primary vehicle so I don't need it to be ultra reliable for the long-haul.

Cheers!

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2001 x5 4.4 125k