98 GTP with excessive pressure in cooloing system

PLease help

I have recently completed a head gasket job on a 98 GTP and all of a sudden after driving it fine for about a week I started to notice a bulge in the upper radiator hose and went to bleed it and discovered a ton of air/pressure
I bleed it all out and it keeps coming back
There is no water in oil no leaks anywhere and Im stumped

Do a compression and cylinder leak down test. Both cold and warm. if you have a leak of combustion gasses into the coolant jacket, it would be happening at the HG.

Which bolts and what torque etc did you use?

Maybe your radiator cap is bad. Did you reuse the stock head bolts or put new in?