Problem with Nissan Axxess year 90

Good to everyone and I thank you for your help.
My problem is that I have a Nissan Axxess 90 Motor Ka24 2.4cc 12 valves, which is producing a fault, the problem is that it costs a lot that turns on and when the engine is finally enclosed by the engine when it is accelerated, when I try to accelerate, accelerate, and only decelerate as it drown and I no longer know what to do, a mechanic already saw it and told me that it was the air Change, and follow the fault, then change the gasoline pump, pay you to clean the injectors, clean the IAC valve and remain the same and I no longer know what to do, please help.