So I've been having this souttering problem since about a week after I put in a new fuel pump in my car. My car is a MY2000, 512WHP. GT3076 turbo. Built motor. ID2000 cc injectors r5671-9 plugs. So I have this sputtering problem when I go anything over like 5% throttle from 3-6k and then when I go WOT the car doesn't have full power. Like it still pulls but feels like a 300whp car, not my usual 500+whp (I can tell a lot) and when I go WOT it sounds different. Like a lot more wooshy like windy like air going through a hose almost. All I've done before this problem was have my exhaust mani not connected to my turbo for a few days before I realized it was the cause of my no boost. My fuel pump died shortly thereafter (it was a walbro 450) so I got an AEM 320 (suggestion of the shop) and swapped it. It ran fine for a week or more then one day it started this souttering nonsense. I've since changed plugs and swapped a new coil around and nothing. I've checked all my injector cables too. All good. It sounds okay at idle. Every so often it'll like hiccup but nothing I can't remember happening before. I need help, I'm at my wits end.

 

I say it's a boost leak, exhaust leak or bad plug and play injector clips. Most likely it's the clips.

 

Clips...I was having misfires/hestitations and replaced my coils...still getting misfires...new clips no misfires...