Rep Power: 0

My 2001 (106K) EX Auto starts right up without fail, always.
Then, it either runs great, OR it begins stalling out within 30 seconds. When it stalls, I take my foot off the gas and let it go through about a minute of trying to stall out, but the engine never dies, it always catches just before dying - and after a few iterations of this behaviour, I can then try giving it gas, and if it is ready, I can go on and everything is fine.
Also, it has done this after the engine is warmed up - I have stopped at the store, hopped in and pulled out into traffic to have this happen, usually at a busy intersection.
I'm taking it to the mechanic for this particular issue, and to get the first replacement timing belt, just wondering what could be causing this....thanks in advance!!!