Injector diffusers for stock rails
 

I'm still have a problem what seems to be a huge vac leak (starts upd and idles around 2300rpm then starts surging from 2000-2300 rpm).
I never used diffusers when I put my stock fuel system back on, could this be a cause? I searched but no one really gave a for sure answer if they are needed.
Thanks, here's a video

http://i11.photobucket.com/albums/a1...0517-00000.jpg

The diffusers are placed in the intake tract to help turn the fuel into a vapour, in a high out put Engine that is run at wide open throttle ,they may not be needed but to improve gas mileage at regular (slow) driving they work . If you have a serious leak try spraying water on the engine, if it stumbles when you spray water, on the vacuum manifold and the vac hoses next, listen for a HISSSSS,and locate the leak , then fix the leak, it may be the intake gasket,or a warped turbo intake manifold ,or poor seal under your primary injectors( bad o rings,or improperly installed o-rings,or a bad hose try it and see............................................... ...........................good luck........................Fred

Wild guess would be a leaking LIM-to-housing gasket, if you don't have a S/S gasket installed there.

Never touched the LIM, just took the UIM off and put a different gasket on. Im going to stary spraying water around there to check for leaks when I get a day off.
Other than that, does anyone think its anything OTHER than a vacuum leak?