I bought a Autometer cobalt egt gauge last week. Installed it about 3" down my header from the engine in cylinder #3. The problem is that it is extremely inconsistent. The highest it has ever read (while cruising at 60 in 5th) was well over the 1600F mark. If i had to guess it was pickup up somewhere around 1800 but the numbers dont read that high. The lowest it has ever read (also while cruising at about 60 in 5th) was 700. I think it seems to be dependent on the outside temperatures because usually when it is hot outside it reads colder and when it is cold outside it reads hotter, but I have seen this theory disproved once maybe twice by it changing from 800 to 1400 in the same night within a couple of hours. Any comments would be much appreciated.