Runs bad after 4000RPM

[Andrew7dg]

So I have aquired a new DSM now but like all dsm it came with some problems I am hoping to fix.

The car is bogging down around 4000 RPM or around 8 psi (so says the stock guage, I will buy an aftermarket soon) It hesitates and stumbles but not that much. However it doesn't rev like it should.

Now I have heard of a couple of solutions to this problem

1) Boost leak however someone did a leak down test and didn't find anything however I it probably wouldn't hurt to try again. I am wondering though and this could be me being a newbie, I am hearing a hissing or what sounds to be a vacum noise, I thought it was a normal noise for a turbo however i am wondering if it is now a leak

2) Bad fuel pump. I don't know exacly what fuel cut is but could the engine be not getting enough fuel? I just saved myself $100 on buying a 255 pump now knowing that I need the regulator to go with it.

3) Ecu giving out which i have heard that when it does the fuel pump seems to be the first thing to go but it is really the ECU

[Blackcrow64]

First I would pressure test your system to see if you have any boost leaks. Then move onto the next cheapest possible fix, the fuel pump. Then if your still having problems then I'd say try the ECU.

[l_eclipse_l]

Have you checked the spark plugs first? Your solution could be just that simple and cheap. Make sure they are NGK BPR....something like that do a quick search, I don't know of the exact model for turbo plugs. And gap them correctly.