Kia Sephia 2000

Good afternoon everyone, I have a problem with my automatic KIA vehicle 1.8 year 2000, when I stop at the high or traffic lights, it turns off or does as you want to turn off, they already checked the air flow sensor, they cleaned his acceleration throat, cleaned the injectors and nothing.
The mechanic told me that it could be the computer that is sending erroneous signals because it says that the codes that the Scaner gives are wrong, ah and something else I have noticed that when I put gasoline it makes it more often and then decreases, I will thank you for your comments ....

Hello, look at it the spark plugs if they are very spent. Greetings!!

Sorry, I also forget to tell you that the spark plugs and air filter already change, thanks ismael53 ....

Well, the gasoline pump works well for you, then, another thing that you should look at that the gas storage does not have the pipe or the atmosphere placed canister (I say it for what you comment when you fill it), what fault codes does it give you?

I do not remember the number just know it was cash, but the box is in excellent condition, I will take your recommendation into account, thanks .....