Toyota Rav4 Losing Acceleration

[Kingdore]

Hi,

My 2003 Toyota Rav4, 2.0 Petrol started losing power or not accelerating about 1 month ago. I brought it to the shop and my mechanic checked, my injectors, coil pack and O2 sensors. The problem wasn't solved. I took it to another shop and the mechanic checked the spark plugs but the problem remained. Whenever the car reaches operating temperature and it goes over 2000 RPM it doesn't want to accelerate. If I remain 2000 rpm and below it goes, once it crosses 2000 it starts acting up, jerking and not moving. Anybody knows what can be causing this? I also changed, fuel pump, air flow meter and ECM, at this point I am really frustrated, some help will be greatly appreciated.

[Kingdore]

Any advice?