rb20 breaking up not sure whats wrong....

[b00stinbmx]

so i finally took the rb20 out for its first drive after setting timing to 15 degrees and getting it idling good and whatnot. its breaking up though i would guess around 5k rpm with the throttle around 3/5 or more or so. i've already checked all coils, ignitor accoring to fsm resistance specs and they all checked out when i was having my previous ignition issue which ended up being the relays.

but anyway it was poping and cracking pretty damn bad and loosing power it seemd as soon as it was building full boost, so i pulled plugs, it had NGK iridiums in it and on cyls 3 and 4 the porcelin was cracked completely. so i took the advice of most everyone on here and put in bcpr6es-11 coppers at first with the 1.1 gap and started it up and it ran like DOG s***. like im talking barely idling wouldn;t rev up at all past 2,500 or so.... i put gap down to like .8 and still not running well at all. i haven;t even taken it out yet cause its just running very badly. Before when i had the iridium's in it would at least rev all the way up to limiter no problem but it would break up when driving under a load. not sure what else to do here... should i try the iridium again and buy new ones? BTW i've checked everyrhing else. fixed anything that seemed to be leaking. also im running a n60 maxima MAF, not sure if that makes a difference or not.