Nissan Repair: nissan nx fuel in oil, fuel pressure regulator, nissan nx

Question
What could cause fuel contamination in oil? 1993 NX 1600. Car runs fine. Tried changing plugs and wires, thinking one of the cylinders not firing, but still getting 2 quart increase in oil volume in about a thousand miles; oil very thin and gas-smelling. Also notice a rattling noise from timing cover disappears when I change oil. Could it be fuel pressure regulator? Thanks in advance.

Answer
Shawn,

It is probably leaky injectors flooding the engine over time, causing the fuel to leak past the rings and over-fill the oil, with gas.  You could have a blown fuel pressure regulator too.  But, I think the injectors are defective and leaking.  Get a fuel gauge and hook it to the fuel rail and then start the car and after you turn off the car look for the fuel pressure to go to zero.  If it does rapidly you need to replace the injectors.  Now, another thing could be that the fuel pump relay is stuck on, I had that happen to me.  This would cause fuel to cycle through the system with the car off.  IF that happens replace the fuel pump relay.