When asking for technical help at the very least let us know the version of firmware you are running.Cliff's Calibration (Mapping) Guide is a MUST READ: http://www.vemssupport.com/forum/index.php/topic,97.0.html
I use the stock VEMS egt calibration value of 71, and then use the offset to adjust the temperature using the offset using a known temperature source. Boiling water and ice are the best to get your values sorted.