i found the problem but need help from the experts

[1iwilly]

ok i found the problem to my code p2096 which is bmw code 235.
this is on a 02 x5 3.0i engine you know the rubber elbow that goes to the throttle body it has 2 holes. 1 goes to the fuel pressure regulator and the other one goes to the y that connect to the brake booster.when i disconnect that hose from the rubber elbow it has a little bit of vacuum coming from it. but when i disconnect the hose that goes to the regulator there is no vacuum at all.well as a test i tap in to the back of the intake where it has a 5/16 port and ran a hose to the regulator to have vacuum all the time except under load.
then i disconnected the hose that comes from the y going to the elbow and block it so there no vacuum going to the elbow. well i've been driving the truck for 2 days and no SEL it doesn't makes sense but it works. today as to confirm it
i put it back to the original factory way and bam the SEL come on p2096 after 10 mile ride.so my question is why isn't working the factory way.??the reason it gets harder to put my finger on it is because i replace all these=
new valve cover gasket
new intake gasket,new rubber elbow,new CCV+hoses,new air eliminator o-rings, new idle control solenoid rubber seal. so all the seal that could leak have been cover.