Lan-evo boost problem

I'm posting this for my friend who owns a 2003 Lancer Evolution 8.

The car will not fully boost. Under acceleration, once the turbo starts going into boost, it is abruptly cut. He has checked the vacuum lines/intake hoses and wastegate function all of which are ok. I believe he could have a fuel pressure regulator or boost controller problem.

Any ideas or recommended areas to check?

Make sure boost controller is rigged up correctly. I had the exact same problem when I didn't T the proper lines

(bypassed the wastegate all together and formed my own funky connection elsewhere in the vacc system. )

I'm posting this for my friend who owns a 2003 Lancer Evolution 8.

The car will not fully boost. Under acceleration, once the turbo starts going into boost, it is abruptly cut. He has checked the vacuum lines/intake hoses and wastegate function all of which are ok. I believe he could have a fuel pressure regulator or boost controller problem.

Any ideas or recommended areas to check?

What kind of mods does he have? he needs to go over all of his lines to make sure they aren't loose, hooked up wrong, or not on at all....

I will go over the vacuum routing myself when I get a chance. He's kinda stubborn so I would have to do it when he's not around.

As of now, he doesn't have any engine modifications, however he did change the pcv system around but now its back to stock.