Hello everyone,this is my first post since becoming a member yesterday. I own a '90 240sx hatch with a red top sr20det that i picked up from a friend that actually swapped in the motor and got frustrated cause he couldnt get it to run right.Im basically a noob to Nissan so i think i took the right first step to owning this superb vehicle and had a professional shop rewire the engine with a new sr harness and new stock harness. Except that, i have the usual first power mods(turbo elbow,downpipe, full 3" exhaust(no cat),Greddy intercooler kit,hot pipe with Blitz blow off valve,Greddy airinx air filter,Walbro 255 fuel pump,300zx fuel filter, Blitz electronic boost controller,dual electric fans,stiffer Nismo engine mounts,Spec stage 3 clutch and lightweight flywheel combo,some crappy Autometer gauges that were already in the car(egt,boost,afr,oil pressure)who knows if they are working correctly,Ichiba 5 lug conversion,rebuilt 300zx turbo brake upgrade with cross drilled and slotted rotors and Hawk high temp. pads,Tein Basic coilovers(that were already on the car...YUK),Battle Version rear upper control arms,Energy Suspension full bushing kit,Circuit Sports coolant overflow tank(love this piece)..i guess those are more than just my engine mods....Finally to my question, I get a breakup at high rpm ,not always,sometimes it runs strong all the way to redline,is it a fuel problem or an airflow problem? Thanks in advance for any info. Oh and 17" mb weapon wheels thanks to Enjuku Raing!!!!