For those of you with the a GRT.. Both my oil pressure and fuel pressure readings with the engine OFF vary greatly. They may show 1 one time and 6 the next time. This also translates into a higher or lower inflight reading. I have replaced both sending units with no change. I now have another EIS test unit but it does the same thing. If this is the nature of the beast so be it. If not I would like to correct it. Thanks.