my mods are posted in my sig. so please refer to that for mods. Occaionally while in 5th gear on the highway i would try to excelerate and the car would begin to back fire and sputter. when i let off the gas and and tried again it would work fine. but today i was driving home from my buddy's house and the problem got worse. The harder i pushed the throttle the car would begin to bog down to the point where it was making a very loud popping sound. Also it will hit boost cut very early(like 3-4,000 RPMs). also it is making a very loud whistling/screeching sound. also my aps blow off valve make a horrible screaming/leaking sound when it releases pressure. i did a search but only came to a conclusion of a boost leak. I am worried it could be an ignition problem. What all should i check for to find a boost leak and how can i tell if it is an ignition problem?

thank you ahead of time,
Josh

 

Plugs (check and replace them), check your turbo for shaft play.