Sorry been away for awhile
The I/C is from treadstone but I had the boost creep before I installed it to .The creep happens when the throttle is just slightly cracked going up a long hill.Ihave tried a different gauge same thing .I have an AEM Tru boost controller but I have tried disconnecting it with the same results.

 

I didn't think the intercooler was you're problem. I was suggesting that cassey123 may have a restrictive one being he couldn't get his turbo to boost as high as ours will. The treadstone intercoolers are good IMO. Run you're wastegate hose straight from the wastegate to the intake manifold. If it still overboosts I would apply pressure to the wastegate hose and make sure the wastegate opens all the way. When I did this on mine I put a small brazing tip in my torch and applied regulated oxygen to it.

 

You have a wastegate problem or the lines going to it. Just use 1vacuum line from the intake manifold to the wastegate.Disconnect the boost controller side.Also use a new vacuum hose since the existing one might be leaking. If that doesn't help then you have a bad wastegate.

 

If your boost gauge is hooked up before the throttle body you will see alot of boost while going down the highway.