Boost issue
 

After installing the ZZP fenderwell intake my boost is dropping off and not holding at 20 psi like it did with the stock airbox. Would this be something mechanical or something in the ECU?

seeing as your supposed to tune for an intake, its probably that.

Are you tuned? It will flow better so if it's in a stock tune, it may not need to run as much psi to get the output out of the motor.

yes I am tuned but the previous owner had it done so I’m not sure what exact tune it is.

I figured it out, the coupler they sent me was either poorly made or had a defect because it runs fine with the stock coupler paired with the new pipe and filter. Holds boost where it should.

So basically you were sucking in unmetered air and screwing up maf. Did ur engine light come on when it did that before?