Nissan Repair: Nissan 300xz 86 31E, distributor shaft, piston rings

Question
I have a 300ZX 86 31E engine which will refuses to rev past 2000rpm?  ECU just stops giving injector pulse? the rpm drops to about 1600-1700 at which point the injection pulse returns. No relevant error codes are reported and engine/electrics appear ok/normal ANY IDEAS?

Answer
Spot,

It is probably the optical shutter wheel in the distributor being coated in oil.  Over the years, the piston rings weaken and blowby allows the crankcase to pressurize to the point where pressure pushes oil past the distributor shaft seal, causing oil to get on the optics.  DIsassemble the distributor and check for oil on the optics.  If there is oil on the optical shutter wheel get a rebuilt unit.  If none then you are probably looking at the amplifier for the ignition.  Located close to the coil.  When you say the ECU stops giving injector pulses did you use a breakout box or a probe to determine this?  The ECM grounds via micro relays.