Hello,
I have a 2004 A4 Cabriolet and having misfire issue on cylinders 2,4 and 6 all in the same bank. I have replaced fuel pump, fuel filter, plugs and coil pack. Car will have misfires and sometimes dies and would only start if I shoot starting fluid into intake. I am trying to located the fuel pressure regulator which is not on the fuel rail. Can anyone please share with me where I can locate. also any ideas what else I can look at to try and solve this.

Any help would be greatly appreciated