I have continued to have fuel issues. My pump is making noise, and I occasionally stall, usually on takeoff or start, but has occurred during normal running on both city roads and highway. I am sporting a naturally aspirated 6-cylinder B280F engine.

Here is pretty much a log of what I have changed and tested, and in the order I did them:
Replaced all fuses (Not really related)
Replaced air filter (Not really related)
Replaced fuel filter
Tested primary pump (Tested working)
Replaced main fuel pump (Removed generic, installed Bosch)
Replaced fuel pressure regulator (Replaced Bosch w/ Bosch)
Tested primary pump (Tested good, it looks like)
Replaced sock filter in tank

The first time I tested the prepump, I did so by pulling the fuse, and listening to the main pump. The main pump noise changed, however engine performance did not.

The second time was really multiple tests. I used a screwdriver on the sender plate to listen to the buzzing, which I heard. After replacing the FPR and experiencing a takeoff stall, I decided to do an exploratory project on my fuel tank. I removed the sender unit, then fuel pump. I tested the pump by submerging it in a large bowl of water and connecting it to a switched power supply. The pump functioned beyond my expectations, and I am now on kitchen cleanup duty for 2 weeks.

I replaced the sock (which was ripping around the pump intake) and took her for a test drive without any stalling, but not impressed enough to reinsert the trunk and put the computer back in.

The stalling got not-as-bad, but did not dissappear after replacing the FPR, and the main pump is still making a louder-than-anticipated noise constantly.

After the engine has warmed up, been shut down, then restarted, it will do it's stalling hiccup. If I *TAP* on the gas, it will try to stall. If I gently depress it it will not. The harder I tap the less it tries to stall. I disconnected my idle air motor (The 'lectric dealie that bypasses the throttle to regulate the idle) and this behavior did not change, although the engine surged every so often on reconnecting it.

Any suggestions of what I should test/replace next would be appriciated. I do not have a fuel pressure gauge, but if they're affordable I would enjoy having one.
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89 764 GLE 150k/ 86 745 GLE 240k