Having a issue with 98 gst

[hurricanes71]

Hey guys my bros gst is having a problem. When spitting still revving the car up n when it hits 3k its spitting. An when u drive it and soon as u hit 3k it acts sluggish and doesn't wanna go. An u see black smoke coming out exhaust like its running rich. What was cause this. We just threw on a stock intercooler back on it. But spark plugs? Or fuel? It acts like it doesn't wanna go into boost at all

 

[92AWDHX40]

I would check for a boost leak.

 

[Insane20]

I agree. Do you have a aftermarket boost gauge. If so what dose it say at WOT.

 

[hurricanes71]

Yea soon as you hit 3k rpms. The guague stays at 0 wont go above.

 

[Phantom DSM]

Yea soon as you hit 3k rpms. The guague stays at 0 wont go above.

If the gauge is accurate and it wont go past 0 into boost at 3k, then it is definitly leaking boost. Check all your couplers, make sure Bov does not have a leak. Time to boost leak test.