reoccurring problems with the engines/gear

Hi All,

i have a problem with my car and i tried to see some mechanics and didnt get a clear answer as to what it can cause the problem

the problem happens every once in a while and its a little different each time ( like 1-2 weeks between each event)

what happens is as follows : 

once the car started running at like 500 rpm when i was going slowly ( like 10-15 km/h) and the car started to move slowly till i turned it off for couple of minutes and it got back to normal

this happened also once but with whitesh smoke coming out of the exhaust

once the car engine turned off while driving and the gear in D at like 10 km/h 

the car also normally does a loud ticking sound when its moving and accelerating ( typically up to 3000 rpms or so) 

the car is skoda octavia 2014 1.2 TSI ( the Czech Republic version).

Thanks in advanced