Well, it sounds to me like a sensor of some type is failing. If it indeed does run fine that is...
White smoke or semi white can be produced in several ways. One way is oil this is normally a whitish blue to blue smoke and has the apparent smell of oil being burned. Next could be antifreeze when it is being burned it has a sweet type of smell and tends to dissipate in the air rather quickly. Next is automatic transmission fluid which is normally found on automatic vehicles (of course) and its occasionally drawn into an engine thru a vacuum line via a defective transmission modulator valve or some other defective part. Transmission fluid is very apparent and billows out so bad that you can't see anything behind you (as does a common blown head gasket). Last (but not least) another type of smoke that is not white but black is the presents of to much gas/fuel being burned in the engine.
With the history of these cars (blown head gaskets galore) (I've gone through 2 peronally) I would personally start investigating if there's any oil in the coolant (take the rad cap off, and look at a near horizontal angle at the fluid. If you see that wonderful rainbow pattern, there's oil in the coolant.) If you change your oil, you may also find coolant there if it's indeed a blown head gasket issue. A compression test is another way of seeing if you've got HG issues.
Also, I'd have the computer flash back the codes to me. This will tell you (generally, since it's not even an OBD1 vehicle, the list of codes it can throw isn't too detailed) what could be wrong.