There is something scary in the suggestion that there may be an additional Gospel. The canon of Scripture is, after all, complete. And I hope you don’t suggest otherwise.
There are about 1,500 scribal errors in the Hebrew Scriptures. The letters vav and yod, for instance, were often confused by ancient copyists of the Bible. The two letters are so similar that they are easily confused. In fact, writing by mistake a vav instead of a yod, or vice versa, is the most common scribal error.