and that may possibly be, which at idle is irrelevant (actually probably better for emissions). once rolling, that is not the case...the area removed is still well contained by other items that block most heat.
highway mileage, throttle response and drivability all had noticeable changes.
current mileage on long trips (with lift and larger tires) has stayed the same as when original tire size was installed (it had slight gains with original tire size)
throttle response and drivability, both showed effects.
they was affected in a matter that this created a small dead spot in the pedal at off idle, low speed, low throttle input (you needed to use more pedal to drive through it)
never said this mod was an improvement, nor is it for every one...this was a trial that i have done to most of my vehicles...i actually took small windows at a time, most having no change to low speed drivability...but there was a sound and mileage change with all.
it wasnt until the majority of the lower box was removed that the dead spot appeared. but again, i knew this was a possibility, but was looking for the gain at higher speeds as we perform long road trips regularly. since having the vehicle tuned (i have a diablo intune3) the dead spot is gone. either by the tune itself or the pedal sensitivity input changes.
the whole point of my post here was to inform that there probably isnt anything wrong the OP vehicle...but that the open flowing elements do create a louder engine noise when throttling...even the posts of swapping to the L83 to L86 intakes on a 5.3 increase sound.
my end game is to have a better flowing, much nicer appearing intake, this was all just a trial...but i can assure you, what ever route i do go...a K&N will NOT be my filter of choice. filtering and flow are 2 very different topics.