hi guys i changed primer pump and it went hard when primed unlike old one so result on that, opened injectors and cranked over till fuel came out, fired up left it running for an hour then drove it 20 miles , turned it off went back and wouldnt start , on the 20 mile drive it cruised along at 85 no problems , but on lev revs it was missing, so i wonder if air is getting in somewhere else, any ideas would be a good help