It would be almost impossible to mess up a water line and have it feed into the intake. There are no intake entry points for that to happen. On top of that, an injector o ring can have a leak that seems almost intermittent, and will almost always fade as RPM's increase, and get worse at idle. Its' leakage rate is dependent on variable fuel pressure and RPMs combined. Test your fuel pressure first. Check the FAQ section, there are a couple of good write-ups on the dremel method of changing injectors. this way you will not have to pull the plenum. If you do choose to (or need to) pull the plenum, then go ahead and do the water line bypass. It will make things much easier in the future. Hope that this helps.
