Fuel leaking and engine jerking

[3l3ven]

Dear experts,

my wife has a XP9F, 2SZD Yaris from 2006.
Last year in summer the fuel started dripping from the neck of the fuel filler pipe when we top off the tank. At that time were a few small jerking as we realized later.
A technician replaced the fuel filler pipe. After we fill the tank full again it was dripping again.
Because of a reason we went to another technician. But that time the engine has started jerking more often, even stopping when it was idling and the fuel was still dripping. The weather was hot. Around 30-33 Celsius.
So the technician replaced the carbon filter in the fuel system. But by then it was autumn.
Everything seemed fine till this year end of April, when the leaking started again. And there was a slight feeling about the engine jerking.
A holey pipe was found and replaced by the technician. After that and a fuel top off, the car is rolling like it would had cube wheels. Now there is no visible leaking just a very strong fuel smell.
As it seems to loose the fuel cap helps a little.

I would like to ask, has anyone experience like this? Where should we look?

Thank you very much!