Engine stalls?

[Betta-j]

I have a 2001 Toyota Sienna.

Just recently I have had problems starting the car up.
It would start, but then turns off after huffing and puffing under 1000 rpm.
I would switch the car on again, but after I rev it up, then the rpm goes down and turns off yet again.

It's not all the time that this happens, but I've noticed it doing it more.

Any clues to what my problem is?

If you need more information to diagnose, I will provide..I just don't know what to write but the symptoms.

Thanks in advanced!

[DaveRT]

If it were mine I'd start by cleaning the throttle body and IAC. I'd also check the throttle position sensor.
If the CEL is on then take it and have it scanned for codes.

[chuck's sienna]

Iac