Hi I have a 96 sari bonneville with a 3.4 pulley. My problem is it pulls about 9-12 lbs of boost when the motor is cold but when it gets up to normal temp it only pulls a max of 5lbs if boost. Any segestions?

Check the vacuum line connections, like under the supercharger snout on the LIM. Make sure the T isn't cracked.

Sometimes it is hard to tell if they are cracked. Wiggle them a bit and see if they disintegrate in your hand = P This is what I would check first as well.

All vacuum lines and elbows good.

Does the boost control actuator move?

Yes free and smoothly open and alaway closed

Do you notice a lose in power when it'* hot? I wonder if there'* a problem with the supercharger rotors.

Yep after it warms up and I've driven it a while it slowly looses boost

Can I replace it with a gen 5. Supercharger?

You can. I'd suggest figuring out the issue first though.

Likely you are getting KR. KR is knock retard, it is the pcm pulling timing, dumping boost etc to save the motor from predetonation.

Beyond the 3.4" pulley, what other mods do you have?