It idles rough and smokes sometimes, it will die when you put it park, but sometime it will idle normal and not smoke, it runs good on the hwy although, I put a o2 sensor today but didn't help. It seems to use more gas when it is smoking alot.

white smoke is normally water in the combustion process
have a compression test done to check for head leaks (corrosion)
have a cooling system pressure test done

White Smoke...
1. Typically normal condensation in the exhaust system converting to steam once engine is running and producing heat creates white smoke. Typically this lasts only a short period of time until condensation water in the exhaust system is gone.

2. If there is a problem, persistent white exhaust could be an indication of a water leak into the cylinders (e.g. cracked head or leaking head gasket. The good news is, this second case will normally will occur with other problems (e.g. consistent rough idle, or rough engine vibration at specific RPMs). If this is suspect, keep an eye on the oil with the dip stick and during next oil change (If any of the oil appears WHITE, there is a problem.). If this is a suspect problem, a test for the DIY'r mechanic would be to remove all the spark plugs, have another person turn the engine over, and watch for water mist to spray out of one or more cylinders.

Because you said sometimes, this sounds like normal condition.

Better get this one to a mechanic. Sounds like you blew a head gasket.

Sometimes that's caused by a vacuum leak near the manifold area.

Sometimes air in the coolant will cause an idle problem. Air will keep the air temp sensor from sending proper info.
Hope this helps.

Replace your hose going from intake to brake booster ( vacuum leak) check all other hoses also. Clean the throttle body. And a tune up probably wont hurt either.

Could be a idle air problem. The injector could be leaking when you shut it off ..Try some injector cleaner see if it gets better..The idle air shouldnt run rough just idle real low or sometimes it will get stuck and idle high....Are you losing any antifreeze..If you are the 2.0 SOHC engine bad about leaking antifreeze into the cylinder and makes the engine run rough until it burns it out..See if you can see the smoke coming out when it happens..White smoke indicates antifreeze,,Black smoke indicates fuel..

fuel injected?try replacing the fuel regulator

check to see if the ground wire from the battery to the engine is tight if the cable is loose it will cause the injectors to flood the egine

coolant temperature sensor boken, check and replace if defective.

i have a nissan b-14 idle roughly sometimes cut off when in traffic. any solutions???????