Back fire and stumble under boost

[RichL19]

I just installed an Evo3 16G Turbo I have the boost set at 14psi, it's as low as I can get it. Problem is when I Build boost in first gear I hit full boost around 3200 Rpm But the car will lose power and slightly Stumble untill about 4000 then it Will pull real hard untill about 6000rpm but then there is a really loud back fire sound, like a bomb going of so obviously i let off it seems to do this in every gear. I pulled the plugs and did a boost leak test a found some small leaks but i think I have those fixed. he plugs look very white however they only have 850kms on them is it normal for them to be white like that when there farelly new or is my car starving for gas. DSMlink is in the mail.

 

[oldman]

did a boost leak test a found some small leaks but i think I have those fixed.

Make sure....The system should hold 20psi for at least 30 seconds upon completion of the pressure test.