after i start the car it idles then the idle ceases and then dies

info about motor etc

stock d16z6 put back into civic after gsr swap...car is a 95 civic ex coupe...everything is on except for the cat because of the extension added to it in order for the gsr to bolt on(i doubt its that because i have cranked over motor without the cat hooked up)...oh yea and the pulleys for ac power steering arent hooked in....i also am reading a vtec solenoid code(can that prevent to cease after)...the mian thing is i crank the car over it starts idle sounds stock and fine...but then its drops and then the car idles so low it stalls and dies....everything i see around says iac, vacccum, blah i was wondering if the cat and the vtec soleoid also prevents from starting and idleing stock...pelase any help would be great...i dont want to send to shop and waste money if i can do it myself

 

As much as you say, "Blah", it sounds like IAC to me.