Hi all, have a 1993 Maxima with the VG30E and all of a sudden it has starting idling really rough and shuddering a bit under acceleration. I have replaced fuel and added injector cleaner, replaced and cleaned out the air filter/intake and replaced the spark plugs but the problem still persists. Any ideas? Thanks in advance

 

check for vacuum leaks, also when was the last time the distributor cap and rotor were changed?