my 97 4 door vitara with 1.6 engine AT is having power loss when AC is on or ascending a ramp or uphill pavement, or fording floodwaters. RPM is very slow to go up when on D and running.

My first doubt was the fuel pump. I had the pressure checked and its about more than 35psi. Would it be the fuel volume coming from the pump be too little even it has the correct pressure? Do I need to replace the pump?

If you don't have enough volume then the pressure will drop, if it was tested static then ithat may not be a reliable measurent. Its not unknown for bad connections behind the rear bumper to affect the fuel pump but more common is a partially blocked filter. The other thing to check is that there is a good connection between the A/C and the ECU load input. These aren't the biggest engines around and some power less is inevitable

more checks where done on the fuel pump and everything is fine.

Next step is have the injectors and throttle body cleaned. Now my question is how do I clean the injectors?