dead injector causes?, damn damn damn... Options

[presure2]

hey guys, been working on the 5sfte like crazy, took her over to the exhaust shop had the exhaust done yesterday, now i can tell that its running on 3 cylinders.
so, i start pulling wires while its running to find the dead one, its #2..ok check spark, thats ok.
so we move to the injector
i have a stethiscope, so i used it to listen for the injector "tick"
no ticking in #2, all the rest seem ok. so i pulled the plugs. #2 looks like its never fired once. lol
so, i pull the rail, pull the injector, and swap it into #1 cylinder. now that ones dead. so its DEFINETLY the injector...ohm test, 15.3ohms, just like the rest..so i pull it again, soaked it overnight in 93 octane and fuel injector cleaner mixed, (about 1QT to 1 bottle of cleaner) and reinstalled, nothing.
these are the 315cc injectors that i had cleaned and flow tested and all that by rc engineering a few months back, and one of them is dead??!?!?
dont make any sense at all...lol
a friend is sending me another injector overnight, so i "should" be all set tommrow, just trying to see if anyone has seen or heard of anything like this before??
TIA
manny