Fuel should be cycling in and out of the pump at a good clip at idle. Now you can't seem to get it to idle well so that might be hard to determine. But at full on run it would really be cycling through the pump. So I don't see how a restriction would be possible. Oh, Have you pulled the out bolt off and made sure that screen in the insert is clean. Back flush the out fitting using some fuel and and a short piece of tubing. Maybe the piece that normally goes between the filter and the pump. Put the out bolt in the fitting and plug the little nipple with a rubber cap and see what comes out. I inspect using a mirror and the sun. Small hand held one to shine light into it and look from the side. I have picked little pieces of crap out of there in the past. Some old O ring or the like.