If the pump is running and does not sound like a bag of nails always check the pipe work for kinks or damage. Then check the inlet filter. Take it off and clean it properly sometimes it looks clean from the top of the tank but can have a transparent film over the gauze. Take the top off the pump and check it is not 1/2 full of crud. See if it works the same with all tools. Get a connector the same as the tool and put it on your solution hose and try the pump freeflow, if it flows well then look at the tool jets.
There are many reasons for poor performance not just a pump on the way out.