my car gets the infamous idle surge but only once in a while, like it will be idling fine then the fan will come on and it will start surging. ive check all vacuum lines and everything and found nuthing. the motor is a b16a its in my 92 teg. now the intake manifold and the fuel system and everything was in the car on a different longblock and it was fine. then i put the b16 in and it started doin it. any ideals?