Nissan Repair: 96 Altima Engine bucking, phillips screwdriver, optical pickup

Question
I have a 1996 Altima w/ 108k miles that has recently developed an intermittent engine problem. The engine will run fine for a day or two then suddenly start to buck at both high & low speed. The check engine light is not on.  At idle the tack show RPM will surge back & forth from 1k down to about 100 rpm.  I changed plugs in line fuel filter & air filter.  It does not matter if the fuel tank is full or empty. Any suggestion?  

Answer
Joe,

Check the distributor for oil on the optical pickup.  The distributor uses an optical pickup much like a computer mouse.  Anyway, there is a seal under the distributor cover that is prone to going out.  If it does oil enters the bottom of the distributor and gets in the pickup and that causes the engine bucking you describe.  To check it out take the cap, rotor, rotor post and cover plate off and the optical pickup and receiver is within.  To get the rotor post off use a phillips screwdriver as with the two screws that hold the cover plate on.  If you see  oil on the pockup replace the distributor with a rebuilt unit.