Big problem
 

I have a big problem with my 2002 sentra SER. has the 2.5 with the (fly by wire) electronic throttle-body and 5spd. well here's the problem i was driving on the freeway (75-80mph) from work and the car just starts surging. holding the throttle steady the motor would kinda die out and come back, i pull over and try to rev up the engine and all i get is a 1500rpm rev from full throttle. im like wtf is going on....so i shut off the car and make a few phone calls when i start the car up its doing the same thing, this time i saw that the check engine ldiot light was on. so i let it sit for a few minutes and try it again, works fine so i take off then it happens again. so i diceded to pull over again and call a tow-truck. ($150 later) i start up the car again for a friend to look at. works great so i let it warm up and it happens again. I am clue less???? im going to get it scaned for the code tomarrow but this is boggleing me. pleas help let me know [sm=dontgetit.gif]