Sounds like a vacuum leak...see if you can hear a HISSING sound while the engine is idling....trace the sound back to the source & repair that leaking hose.
If you dont' hear any sound, then put the ECU into diagnostic mode & see what codes kick out.
For instructions on how to put the ECU into diagnostic mode go to the FAQ page on
www.240sx.org
Click on Engine Trouble Codes...SOHC...
Hope this helps..
ID
'95 SE