Camaro problem

Hi, I have a 1992 Camaro RS with a 305 TBI. Just starting yesturday. Randomly while driving the car started feeling funny. I pulled over and noticed the car was trying to slightly accelerate while my foot was not on the gas. Then the engine light came on but im not sure if that had anything to do with my problem because it was code 15 which is low temp at coolant temp sensor. I tried putting the car in neutral to see what would happen and the idle speed went up to about 2300 which is really high. I let the car idle and it sounded kind of throaty like it was about to stall. After about ten seconds it did stall. If im driving and dont let the car idle for an extended period it wont stall and the engine light goes off and the problem goes away. But comes back in a little bit. I noticed white smoke coming out of the exhaust when I rev it while idling. Not alot of smoke but it usually doesnt smoke at all. Any help is appreciated