eversince i put on my rtek 1.7 randomly during idle my car will start to sputter and the afr;s will slowly lean out till it gets to about a 16:1 and then just kill the motor. it will start right back up no problem and most of the time not do it again, but it happens about once a day. anyone know what it might be? i have a s4 tII with stock ports and turbo and 550/860 inj. with all bolt ons. any help would be awesome.