Why has my engine all of the sudden started to drop to rediculously low rpms and stall out every single time the car is in park or stopped at a light. Everytime I brake pulling into my driveway or a parking spot the engine shuts off causing me to coast.

 

fuel pressure problem, filter clogged or pump going out.
timing problem, chain streached, jumped a tooth.
vacuum leak, check by praying carb cleaner or wd40 around motor when running.
Hope that helps.

 

this is happening in combination with smoking from the valve cover hoses and a major oil leak if that helps narrow it down

 

Could also be as simple as dirty/clogges IAC. Take it out en clean the IAC passages and lubricate/change the IAC. Then check your minimum air and set it to correct rpm and the adjust your tps to 0.54V

Check if it helps.

 

You know it may be more that one thing also. Check the free and or easy stuff like a tune up. Plugs, wires, ect. And as theking said check, clean, set.
With the new oil leak and smoke maybe your motor has clogged breather/pcv system, making pressure in the crank case and oil pushing out the gaskets and rings not sealing. BUT do the easy/ free stuff first. Check the last thing you did after the problem started. Consider the mileage, use/abuse also.