Concentrate on the mis first. There is going to be gas on the plug of the cylinder that isn't firing properly so don't let that bamboozle you into thinking that excessive fuel on one cylinder is the problem. Maybe redo the compression test and do 4 compression strokes instead of the 10 seconds or whatever. Does number 5 seem to run for a while after the codes are cleared before it starts to mis again?? Any black smoke ?

As far as fuel pressure, the gauge needle should shoot up quickly when pump starts with key on then drop a chunk when the fuel pump stops after a few seconds. If it rises slowly or doesn't drop when pump shuts off then you don't have a good connection to the rail. After that check that the rail holds pressure. with the pump off.

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1988 325is (purchased new) sold
2004 X5 3.0 2005 X3 2.5
2008 X5 3.0 (new to me)