Losing boost at higher speeds

[99GTPMLA]

Something I don't notice that often because I don't often go this fast, but when doing wot, when it gets up to 90mph, my boost drops off and the engine sounds quieter. My boost gage drops to about 1/3 to half and the engine seems to lose the growl and a little power, but it still accelerates. It seems to only happen at around 90+mph. Anybody ever experience this?

[gunsandweed]

This happening on a 99 GTP?

I would scan parameters on a normal drive and while doing pulls.

[Anthony Smith]

Its possible that it is going into cat protection. When I first got my car done it would lay over around 115 and lose boost. Turned the catalyst over temp protection setting off and it cleared right up.

[99GTPMLA]

Yes, this is a 99 GTP. I have a ECU with dsmuts program and don't know if it's going into cat protection. I didn't even know it had that feature.

[Anthony Smith]

Yes, this is a 99 GTP. I have a ECU with dsmuts program and don't know if it's going into cat protection. I didn't even know it had that feature.

Me either I found out the hard way. In the supercharger table there is a box called "cat over temp boost reduction" or something to that effect. Once certain conditions are met while holding it wide open it commands the boost bypass solenoid to open. I had to go in on mine and turn it off