This may be a stupid question but the Haynes repair manual has me confused. Is there suppose to be an o-ring in the fuel rail in addition to the o-ring already on the injector?...or is there just one o-ring, being the one on the end of the injector. The Haynes repair manual shows the removal of an o-ring from the rail and removing one from the injector. This leads me to believe that there are two o-rings in there. Thanks for any clarification.