LMM: CAI and MAF sensor

[brunok]

So roommates truck is getting a noise from the passenger firewall area like a air rushing/pressure release every now and then.

Truck was tuned by a guy with EFI that is 5 hours away and very unhelpful.

There is no blocker plate installed but I'm guessing he turned off the EGR.

On the 5 hour trip home he never noticed the noise but it seems like after he installed a K&N system this noise started.

I'm about to put the factory intake back on but any other ideas?

2008 LMM EFI and turbo back 4"

 

[TeaBagger2006]

does this noise happen when the truck is warming up? if so, its the turbo just surging a tad. mine always does it when its not warmed up but goes away after its up to operating temp or near..does it do the sound after you let off the accelerator?
if the truck drives normal and no codes are thrown i wouldnt worry

 

[brunok]

He claims it does it randomly at anytime. I've noticed it under acceleration before...

Anyways he's an hour into a roadtrip with the stock intake back on and no issues. I'm thinking it was something with that air flow sensor and the larger diameter intake... ?