The only thing that causes smoke in a car is something burning. Steam or vapor coming from the air conditioner can also look like smoke. More detail especially where the smoke seems to be coming from would be helpful. This sounds like something that needs immediate attention and you should not be driving the car if you cannot find the origin of the smoke.
If an alternator is going bad it can cause a rough idle in a 1993 Subaru Legacy. Cold temperatures in the winter can also cause a rough idle in the Subaru Legacy.
viscous coupler
Well... Hopefully, for your sake..there isn't any *It will cause a massive explosion*
could be something with the steering or with the power steering pump.
I'm having the same issue, did you ever find an answer to this?
metal rubbing against the tire
There are a couple of things that can cause your middle stop lamp to remain on. The most common cause will be a loose or corroded ground wire.
oil or tranny leak and dripping on exhaust
Bad seal around the bottom of the wind shield maybe?
Unsure where you'll find the bugger, get your auto sparky to replace it (its a MAP sensor) as it can cause real headaches if it dies, engine rebuilds and such
Love.
check fuel pressure, also a weak ignition coil or fould plugs could cause hard starting