Low power at high RPMs after T-belt and water pump change

[DST]

Hi. I have just changed the water pump and timing belt on my 1998 hilux 2,4 TD (LN165). Everything went well. The fuel pump pulley rotated a bit between 11 and 1 o'clock but I rotated it back or forth when installing the T belt så it was on the correct mark. After T belt was installed I checked all the markings by rotating the cranck shaft 2 full revolutions and the marks lined up fine. When I finally started the truck, It is low on power in the higher RPM's. I went back into the T belt and set it again. Everything is lining up on the mark.

The timing is as it should be BUT I thought that the screw in the attached photo circled in yellow was a coolant drain on the motor block and loosened it. Nothing came out so I screwed it back in. The screw is on the fuel pump. Does anybody know what this screw (circled in the photo) is for and the proper setting? I think that's why it isn't running right in high RPMs. I tried to adjust it in and out and there was a little difference but not exactly right. Or is there any other advice for why I have low power? I have bleed the fuel lines several times.

[Bigpete]

Might say take it to a injection shop ,that may have a diaphram in there that may have become detached or misaligned