Can u grease bearings 99 granprix turbo?

You have bad bearings in the turbo charger. Replace unit or remove turbo and replace bearings.

If the engine air filter is good, and the exhaust is not restricted, then check the turbo bearings

Could be the main bearing inside the turbo is gone .. If that is the problem you will need to replace the turbo.

It could also be a leak in one the turbo hoses.

COULD BE WORN TURBO BEARING CAUSING TURBO ROTOR TO MAKE TAPPING NOISE GET A STETHESCOPE LISTEN AROUND THEN ENGINE BECAREFUL WATCH DRIVE BELT DONT GET HANDS, CLOTHES HAIR JEWRELY CAUGHT IN MOVING DRIVE.LISTEN AROUND ENGINE.THE STETHESCOPE CAN HELP YOU PIN POINT THE NOISE.YOU CAN BUY STETHESCOPE AT SEARS OR ANY AUTO PARTS STORES.

A new turbo charger is about $340, but you can buy the bearings and seals and rebuilt if yourself for about $100
http://turbosandparts.com/
It is not hard, and it does not take long to do.

I normally do not bother with synthetic, but with a turbo charger, it might be worth it. What really seems to ruin turbo chargers the most is not letting them cool off before parking.
Once you turn off the engine, there is no longer any cooling, so the build up heat will burn up the oil and seals.
Run the engine for at least 5 minutes below turbo levels, before shutting down the engine.

sounds like the turbo bearings are going.You could use molyslip oil additive,but this is only to coat the bearings it will not stop the noise for long....

A bearing going bad. Do you follow turbo shut down procedures? If you don't have time to do this then my suggestion is installing a turbo timer to do this automatically. When you drive the car specially a high speed and need to shut down the engine is the worse thing you can do to your turbo. The impeller spins double the speed of sound and takes quite a while to slow down specially when you shut down the engine. At the same time it is shut down, oil pressure is no longer provided by the oil pump and cooking from extremely hot turbo assembly. The end product is oil carbonizing and clogging moving parts. The term is called coking. A turbo timer will keep your engine running when you remove the key from ignition and lock the vehicle for a programmable amount of time. This will help the turbo to spin dow while lowering the temperature critical for a longer servie life of your turbo charger.

you probably need new turbo. check oil supply to the turbo. grinding noise sounds like bearings in turbo are overheating do to lack of oil and slowing down the turbo. that explains the uneven boost press.

Whining noise usually comes from defective bearings. have the bearings of your turbo charger checked.

this is not good; you probably ran the turbo bearings dry and they have seized try to loosen the turbo by removing it breaking it loose and lubricating the bearings if they are still good or, find another one at the junkyard