Contour Enthusiasts Group Archives Forums Modifications Forced Induction Used vortech problems

Secondary intake manifold runner valves are probably gunked shut with crud. You'll want to check and completely clean the intake manifold if you haven' already.

Oh yeah, check for a plugged exhaust system, like a bad catatlytic converter. I've had that happen before when installing a component that increases exhaust flow. Check to see if it has stock precats...which it probably does and if so you'll have to check it out.
Drop the catback and see if it revs better.
If not, and you've checked out the intake system, added some decent fuel, then you may want to gut the exhaust manifolds or install MSDS headers that were designed to clear the supercharger jack shaft.

Last, if you have a plugged fuel filter or bad injectors it could cause similar issues.