Volkswagen Touran Timing Belt Problems

at what mileage should the timing belt be changed?? apparently it was done at 60k. car now has 99k on it.

my 04 touran has recently got very hard to fuel.roughly im getting 40miles to £5. i havent changed anything with the car, got new clutch and timing kit thats all.

The engine is going off when trying to put in reverse and some time braking then going off again.

it is chronic and has happened about 4 or 5 times. The lambda probe was changed 4 years ago. the spark plugs and spark plug cables were changed also. why does this keep happening?

My 2004 touran struggles to start under warm temperatures and idles rough, however on a cold start it fires up nicely and runs how it should the idle is also lumpy and I can also hear a faint thumping sound coming from the engine bay while ...

At what intervals should the cam belt be changed on my Volkswagen Touran 1.6 tdi 2012 with 35,000 on the clock. The dealer I purchased from said 133,000 or 15 years, this seems a long time?