The ex-Isuzu dealer here in Windsor, Ontario replaced my EGR to the tune of $300+ a few months ago and cleared up my Check Engine light and noticeable hesitation but the light and a little skip in the rpm's is back again now!!! Autozone said it's a P0405 code meaning the "EGR position sensor BBvoltage was too low". Should I get them to replace the EGR valve again if I can or is it likely something else such as the EGR position sensor itself? Help!