S.O.S 2000 jetta 2.0l runs like Crap missfires S.O.S

hello boys and girls Im new in here :) I have a problem with a jetta 2000 2.0l 90000miles

Car idle rought .no power ,backfire in the air box ,hard to rev up basicaly undrivable !

here the code I got Random missfire

cylinder 2 cylinder 3 cylinder 4

I did a little tune up but still havent changed a thing I changed

-sparks plug

-wires

-coil and module

-fuel pressure regulator (3.0bar)

-fuel filter

I also checked the fuel pressure

2.5 bar (vaccum plugged) 2.9 bar (vaccum unplugged) all at idle

Here a interestng fact if I plug the return line so that fuel can got back in the tank it run and take her gas O.K.

when it warm up it's seems to run a bit better but still hesitate some times and run rought

Guys I you must help me on that one cuz im about to grap my baseball bat

Regards Alex