How many intake manifolds does a 1998 buick park avenue have? Also is this a difficult job to do? I have heard these cars are notorious for melting there intake manifolds, is there a metal replacment of some kind?

https://www.2carpros.com/questions/buick-lesabre-1998-buick-lesabre-start-circuit

If you know how clean intake manifold, MAP SENSOR ,PCV, EGR VALVE, RUN A COUPLE OF BOOTTLES Of SEA FOAM INJECTOR CLEANER IN GAS, MASS AIFLOW SESOR SHOULD ONLY BE CLEANED WITH MAP SENSOR CLEANER !

i took my car to NA Auto Repair they did a great job at very resonable rates

White smoke usually means water in the cylinders. I would say you have blown head gasket or intake manifold gasket. Could be something cracked or something I don't know about. Unless it is something I don't know about will not be simple or cheap to fix.

These cars do not have head gasket problems you need to remove the sparkplugs to get the coolant out and replace the black upper intake manifold as they will leak coolant into the combustion chamber. Common problem.

First start the car to operating temps and check all hoses for any small pin holes that could have sprayed onto your air intake. If you find nothing then it could possibly be a blown intake manifold gasket that is leaking into your air intake

Buick 3.8's are notorious for intake manifold leaks. If you are sure you are not leaking externally (look under the alternator and on the top of the transmission), it could be an intake manifold leak. I've replaced mine...I didn't think it was too hard a job for an amateur.
It could also be a head gasket, but the intake leaks are much more common.

the EGR transfer tube melts the upper intake(plenum) it will need to be replaced

If this is a 3800, Upper Intake Plenum or Lower intake gaskets are an inevitability. Head gaskets on these engines rarely go out! Seriously, don't get duped. I am doing the job on my grand prix right now. Google it for further explanation.

On the passenger side of the black plastic intake manifold. Be sure to put the o-ring back on it or the engine light will come on.