I'm sorry, I'm not the best in english language, but I would like to call for help.
Our client have a Mitsubishi Pajero Pinin 1,8 GDI with 4G93 engine code. The car engine is not working above 4000 rpm, and if I push the accelerator pedal more than about 30-40% or full throttle, engine will be crackling and sometime stop. If I try to accelerate with small pedal position, the engine working well to 4000 rpm. In this engine speed it working like in 8000 rpm (gives a noise like a speed limiter)
I think we find what cause this problem, because we find a big leak in a fuel filler pipe. After that, we performing the following:
- changed the fuel filler tube
- cleaned the fuel tank
- cleaned the fuel supply system
- we send injectors to testing, in 5-6 bar fuel pressure they working well (the garage have only lower ressure injector tester)
- disassembled and cleaned the high pressure fuel pump (it was very dirty inside, and some part is rusty, but we clenaned ererything as far as we could
- measured the low fuel pressure ( I don't remember to the value, but it was correct, maybe about 3,5-4bar)
- we measured CO concentration in the exhaust pipe, it is 0 in every engine speed.
After these tasks, the engine is working same like before cleaning. We haven't got any new idea, what causes this problem.

We have a Picoscope 3432, so if you have any ideas or suggestion, please write me back.
Thank you