Echo initial start problem

[echo00]

Hey everyone, new here. I have a 2000 Echo that just started giving me starting problems. On the initial cold start it starts but dies about 2 seconds in and will continue to do this. If I gas it and raise the rpms before it dies it is fine and runs fine all day. But will not start and idle without me reving it for a few seconds. Just had it tested battery alt pulled codes came out clean all around so I cleaned the pcv valve and throttle body, I havent tried a cold start yet but toyota and my mechanic does not know what it is, anyone have any ideas what it could be or what I might try, Thought it was a fuel pump slowly losing pressure but toyota says no, it works or it doesnt. Thanks guys.

[RningOnFumes]

That's a problem I used to have in my 96 Camry 4 cylinder. I just adapted like you did and lightly gave it gas while starting the car.

At one point I got fed up with it and messed with the throttle cable. That worked, try it, but if it revves too high bring it back.

Now if you are not sure about doing this...don't ask about it when you take it in the the next time.