I have the aem fuel pressure regulator and for some reason, the fuel pressure always flexuate once in a while. For example, I have it set at 43psi right now, some times it will fall down to like 35 or even lower, and sometimes it will rise up to like almost 50psi. Did I just get a faulty one or is there a reason for that??? Oh yeah, and when it flextuate too much it'll set off my check engine light too. Can anyone please shed some light on this????