I am not sure about this because I don't have safety or emissions testing but MSnS makes your CEL stay on unless you remove the bulb due to the injector circuit and o2 sensor not haveing any effect on the fuel trims or being able to complete the injector circuit. So if you have to have a visual and the CEL has to be off, then your not going to pass with MSnS anyway. I don't think any one has isolated the noise but people have gotten rid of the stock ecu and it goes away so I would say its probably something that you have tapped into for the MSnS sensors(TPS, Crankshaft, or something). If you wanted to keep the stock ecu but use MSnS then use an older board, MS1V2.2. Thats what I am going to do.