problem with klze when engine cold

[rythematic@hotmail.com]

Hi im new here...just wondering if i could get some thoughts on my issue....I have a 94 mx3 with the KLZE swap and it has been good to me for the first few months ive owned it...but now I seem to be having a problem when the car sits over night or for atleast 7 hours +/- ...I start the car and it doesnt seem to hold the idle high long enough for cold start and it misses especially if i try to rev it up and if i just leave it alone the idle will surge between 300rpm and 1000 and running extremely rich to the point dark/ black smoke can be seen and sometimes stalling out but once the engine gets to operating temp. it will run fine except if u rev it... the rpms go up as normal but then come down to 400rpm and then settles back around 600-750rpm other then that it runs fine now im thinking maybe I need a new engine coolant sensor...let me know what u guys think thanks in advance!!!