I can't find where anyone else has posted on this, so before I start diving down the rabbit hole trying to figure this out. Driving to work this morning, I realized I had my COBB plugged in and displaying the boost gauge. I was sitting at a light and happened to notice that the COBB gauge had a different value than the OEM gauge displayed in my digital instrument cluster. I then checked against the PP gauge and same thing. The 2 OEM gauges agreed with each other and the COBB was exactly 1/2 the value. Once the light changed, I noticed under varying load that at all times the OEM gauges agree with each other and the COBB gauge was exactly 1/2 the value of OEM. This applied to vacuum only. Once boost was being measured, all 3 gauges agreed with each other. Has anyone else noticed this behavior either previously or currently? I'm going to remove my custom tune and put on the COBB OTS Stage 0 when I get home from work tonight, to see if it is a product of a specific tune or the COBB device itself. Another related question on this would be are the OEM gauges and the COBB using the same source for vacuum. I would assume that since the OEM gauges are CAN and the COBB is plugged into OBD, that it would be the same, but maybe someone knows different. I really would like to get a definitive answer on this to know if it is normal and if not, what I should be looking at as a fix, COBB, dealer warranty, something simple.