2001 Volkswagen Passat Car Starting

i replaced the timing belt on my passat 1.8t and made sure to mark the camshaft pulleys, but now the car has trouble starting and starts only if i press the gas pedal, it also delays on acceleration before the engine picks up, can i just take the belt off and try to realign the marks i made or is there a different way to deal with this because the camshaft has four different rotational cycles? or is the even why the car is having trouble starting? also i can sometimes hear a small backfire when trying to start the engine