remembered you saying you had a Greddy Management system, im not sure what that exactly is, but maybe look there ???
GReddy Electronic Performance System,(Model PRofec B-spec II ) controls the amount of Boost (Adjustable, Hi & Low) you want to run. Not an expert by any means but I believe it adjust's the fuel psi & timing with the AEM computer. Also controlling the Waste Gates. I know it's hooked up to those components.I think it works great, Set boost off, Low or High.
I believe the filters got too wet & cause the problem, because once it stopped raining it drove OK. Mounting the air filters / Intake so low to the ground isn't the best idea, ESPECIALLY here in La.