Since my car went to the extent that it was impossible to start it on petrol so I had to go all out on everything related to petrol. My mechanic opened the injectors and put a cardboard in front of them connect with engine and started cranking. Only 1 was firing perfect 1 was entirely blocked and 2 were irregular in firing he tried cleaning it by carb cleaner but that did not help and I bought kabli 4 injectors in 3500rs and working fine.
After I had got the work done I got a pm from a fellow member stating that they do ultrasonic cleaning of injectors and as he said and is also true that it is the authentic way to clean injectors. I think he quoted 3000-3500 rs for 4 injectors as I had already replaced my cars injectors so I said that I have already rectified the problem.
I know that there is workshop here in lahore who is also offering ultrasonic cleaning and they also charge 3000-3500 rs i am not sure. Concern here is that what is the solvent they use to clean the injectors. The original solvent is expensive and if an improper solvent is used for cleaning it will damage the injectors. Since I bought the car second hand so I had no history so the cheaper and wiser option was injector change.
But since I have experience this sluggish response from my car and have gone through it I can say just change the pump and you will be fine.
Regarding pressure well last pump that I bought in 800rs was good in pressure, but the mechanic from whom I got it fitted was not my regular one and he left one of the pipe loose from its housing although the connection was perfect but due to pipe not sitting in housing the guage could not move so I cannot tell at what level but sometime back the fuel got really low and the pump started making goon goon sound and the car suffocating since I was near a pump so refilled fuel worth 500 rs i.e 5 ltr. As I was not too far away from home just 2 kms so went and parked the car next day went for refill and it was some 30 ltrs for full tank. Now take that 30+5 35 ltrs. So remaining fuel is 42 ltrs. Now 7 ltrs was left when car was suffocating so this is the level of reserve I think. Also I would like to add is that the pump was noisy from the start and that goon goon went away after complete refill. It was some 2 months back the pump started to make goon goon again but only if the car was driven for 50+ kms or with fuel under half. So I changed the pump before hand because I knew it was starting to take extra load.
The pump I replaced with the pump costing 1500rs and went on a road trip to rawalakot. Recently I did 580+ kms in a single day with this pump with ascends of pir sohawa and salt range and allham dullilah no problem.
Regarding fuel level well since you are using the car on petrol so what is the point in emptying the tank before each refill, Atleast I think it is better to refill when the tank reaches half.