hey i got an ls vtec and i had the usual idle air valve problem, cleaned it out and adjusted the idle screw and now the engine rpm fluctuates up and down between 1000 and 1500rpm, but after that everything runs smooth, has anybody had this problem before or does anybody have any suggestions? thanks. by the way it has a p14 ecu

 

throttle body maybe...take off ur air filter and see if ur trottle body is sucking on air from the holes and if it is put ur finger on it and see if it idles fine after that

 

my ls vtech was doing the same i cleaned the throtle body and i installed a fuel pressure regulator and i never had a problem. o and did any one have a prob with there rpm gauge it wont work ever since i did the swap

 

YOu should get it checked out by a professional if nothing you try works.