Try to make your throttle cable tighter on the throttle body don't tighten it to much. My car does this when it's cold the cable has a plastic slip tube on the throttle cable on my 96 and that keeps lipping and then my idle drops all the way off usually stops at 900 rpm.
Try adjusting the idling speed - sounds like idling speed is too low so when you take your foot off the gas it can't idle (Tick over)
Gasoline
The Volkswagen Jetta was produced from the years 1979 to present and the oil capacity for a 2009 Jetta 2.5 is six quarts. The type of oil that a 2009 Jetta 2.5 will take is 5W-40 or 5W-30.
Idling too fast. Set the idle to factory specs. Should be around 750 RPMs in neutral with A/C off.
It could take an estimated 1/2 gallon to 1 gallon idling for a hour.
ON MY 2003 JETTA YOUPUSH IN ON ONE SIDE AND SIDE TO TAKE OUT. BE CAREFUL AND DON'T BREAK THEM.
I have a 99 jetta, and you are unable to check the transmission fluid on your own. You will have to take it to a service station where they will check it for you for free.
Check the fuse box, often there are idling regulator circuits that have simply blown a fuse, these are also the easiet to overlook.
Its sealed, you have to take it to the dealer!!!!
Take it to a repair shop!
4.5 quarts
30 seconds of idling equals one average start, on a normally-functioning start.