Car problem, need your help.

I have a 2000 Honda Accord EX V6. Whenever I am in stop and go traffic (driving like someone is in a rush, pump gas hard to change to a faster lane) my car will die after being off for 30 min. For example, I will be in stop and go traffic jam and then I will stop by a restaurant for a quick bite, then when I come back out in 30 min. my car will start then the rpm will drop to 2000 and my car will start shaking, then dropped to 1000 and then dies. In order to make it don't die, I have to step on the gas, then sometimes it's okay and sometimes the rpm will just drop straight to 0. It seems to happen most with I use Shell gas. Not sure if that's a factor because Shell gas seems to be appraised by many people.



I have took it to the mechanic and changed:

the coolant temperature control

air filter

oil change

spark plugs (not wires)





What do you guys think is wrong with my car?



Thanks.