idle and stopping problems.

[HighPsi92GST]

my friends car (92 tsi FWD) has a 16g turbo and a boost controller, k&N intake filter, hacked can, removed honeycomb stuff or whatever, EVO3 ported exahust manifold.
now he just got the 16g put on to the car and its running ok. gets boost and everything seems fine. BUT when hes going up to a stop sign, when he pushes in the clutch and the brake pedal to stop the car shuts off. also sometimes when he pushes the gas it will hesitate for a second.
what could cause this? he says it dies everytime he tries to stop somewhere. and when its just idleing everyonce in a while it will run alittle rough than pick back up.
other then the stalling at stop signs it runs GREAT with no problems and idles fine except for a few seconds everyonce in awhile that it slows and then picks up again. any help would be greatly appreciated...just need ideas on what to look for....

 

[leet]

Tell him to put the honeycombs back.

 

[HighPsi92GST]

would putting them back solve the problem? and what if he doesnt have them or it anymore? im not sure what the honeycomb is...that thing inside the intake that looks like a honey comb im assuming.... well if he should put it back, and doesnt have them...then what?