trouble accelerating on 2002 Buick Regal

my car does not accelerate properly. the rpms go up but it takes an unusual amount of time for my car to get up to speed. also, when the car reaches about 3500 rpm all acceleration stops and a knocking/ticking sound occurs any idea? price quotes?

These 3.8 engines are notorious for cracking the intake manifold, check it for leaks.
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My last Buick (Park Avenue) had a similar problem.. but only when less than 1/3 full of gas. Could this be the same? If so, try keeping the tank above half and that should solve the issue... worked for me!