I told you not to stuff your dirty underwear in your intake pipe.
It could be anything. just take it to a mechanic. dont bother posting on TR on such a broad issue, it will only confuse you and us.
i really dont know why you cant use google.com
If the "check engine" light comes on in you cluster, check the ECU. its located on the front floor on passenger side. theres a thin plastic cover on it next to the door panel. remove it, then turn the knob one way than back, then read the flashes that it gives you which is your code. then search for the 240sx manual online which you can download and look up why your motor is whining about.
If you dont know what im talking about, use google seach or make friends with a mechanic. good luck, i know you will need it.