Volvo wont start

my car wont start unless i rev my engine up for a while. this is only after it sits for 3 or more hours. battery is new and it has been looked at by a mechanic who said nothing was wrong.

How do you rev your engine up if the car won’t start? Seriously - people would need to know if anyone is going to comment.

Or do you mean that the only way to get the car to start is to floor the gas pedal, and keep it revved up after it fires? If that is the case, then you likely have a leaky fuel pressure regulator or leaky injectors that are flooding the engine when it is shut down.

yes im sorry when i turn the car over if i dont rev the engine up it just stalls right away i have to rev it for probly 20 or thirty seconds for it to idle