pls help me fix my 240 ! :(

[mike fonseca]

I have a ka24de that came off a 97 240sx i dropped it in my 91 240sx i kept the same harness i just changed the intake manifol it ran fine for about 7 months n now its acting up ... when ever i floor it the car will bog out at like 45k rpm it feel like if i would b at red line n it dosnt wanna move it just starts jerking back n fwd n also wen ever i floor it the temparature gauge shoots all the way down like of the car would b cold and the check engine light comes on but since im driving wen it happens it always shuts off wuth in accupple of seconds ... and its been runing for a wile n i turn it off n try to turn it back on it wont turn on i have to keep trying to popstart it n it only work sometimes i usually have to wait for a wile before i can turn it on n wen it does come on it shoots a big cloud of black smoke n it smells like gas n it sounds like a suburu at idle for a little wile then it sounds normal again ...... some one pls help mee !!