I drove this car about a month with a slight rattle from underneath. It is an auto transmission. It started stalling on me in every gear but park. While in park it vibrates a lot now and I drove 40 miles after putting a quart of oil in t and it used it all but no evidence of leaking where the car has been parked. Help do I need a whole new engine???
Probably needs a visit to a mechanic. After that, who knows? I think it is unlikely that the car burned a quart of oil in 40 miles because that would probably generate a smoke plume that could be seen for miles. So, that oil is going somewhere. Perhaps it is in the coolant. Perhaps it is puddling in some cranny.
The rattle from underneath could well be innocuous – a loose heat shield.
The stalling could have a multitude of causes in the fuel or ignition systems and might or might not be expensive to fix.
Cost to fix? Who knows? Somewhere between a few hundred dollars and more than you will want to spend on a 1994 Toyota.