Hello pls, can you just assist me on my Nissan Maxima 1999 auto transmission, with a stalling engine issue, when engaging the gear, say from P to R. This started when the engine oil was changed, with 2 plugs. Though, it would engage d first time the engine is started for the day, but when it gets warm an you try to off the engine, then restart, but engine will go off as you engage the gear. Some 2 days proir to this problem after the oil change. There is a white fume at the exhaust pipe when it revs. What can be done pls?