P0300 / Engine RPM speed @ idle

cheshirecat

It doesn't happen more in different years that I know of- it seems to be broadly related to the intake design of the HR motor (both 35 and 37). I wouldn't say it's bad detection logic as much as the engine just sensing more air (lean mixture) that could cause a possible misfire condition.

IMO, this code is much less severe than the actual misfire code that specifies a cylinder. In that case, I would look at the connectors for the coil packs as well as the coil packs themselves for the specific cylinder specified in the code.

It personally doesn't make sense to me that the Stillen (or really any) intake triggers these codes so people automatically assume something is suddenly damaged or that a sensor has failed somehow.

IMO, in these cases where the intake is installed and the code just starts popping up, there's just more air getting into the engine which passes a pre-programmed threshold which then trips the code. That's just my guess- please don't take it as a definitive conclusion for why so many people experience this issue.