I have a 1999 park ave with the reg. 3.8 (not supercharged). The wife was on her way home yesterday and the service engine light started flashing and a bell kept ringing (like when the door is opened). The car lost power and she said it smelled like exhaust fumes real bad. She drove it about a mile to get it home. She said temp gauge was reading normal. When I checked the radiator it was almost empty. My question...is it the intake or head gasket? And did driving it possibly toast the motor? And the strong exhaust smell...Plugged catalytic converter? Also she said when she stepped down on it when it was losing power, white smoke came out the exhaust. The motor has 170,000 miles on it.

Yup, tell tale signs you lost one of your intake gaskets. The flashing check engine light indicates the engine is misfiring. Big time. This is because coolant is getting mixed with the gas/air mixture and causing havoc during the firing process.

First thing first, check your oil level and the condition of the oil on the dipstick.
2nd, don't deviate from this list. Change both upper and lower intake gaskets and get the metal framed lower gaskets. Replace coolant elbow with aluminum style, change the oil and if need be, flush the cooling system.

Dont attempt to start the car until above is done..Mike should he not drain all the oil & coolant now?

I would if the oil is visibly contaminated.

I would usually wait til I got the U/LIM off....then I would run a quart or 2 of fresh oil the the valleys to make sure there'* no Anti freeze trapped while draining what'* already there...done this a few times for people who thought there motor was gone...

Not looking good with the white smoke...it means it'* burning up in the cylinders....good advice from everyone....if doing the lower intake gaskets, make sure you look for degradation in the EGR passageway of the upper plenum....

In addition, I would still do a pressure test, to check for external leaks.......hate to do all that work, and still have an external leak, like a hose, w/p, radiator, etc.

Key, is doing the work right away, and not just changing the oil and adding coolant as necessary, to be able to run the car....

What he said^

What they said ^^...Torque those bolt...don't wanna over tight those!!

Thanks for your advice guys. It'* much appreciated.