This is the same post I put in the Pathfinder forum, but I wasn't sure the best place for it. Thanks for understanding:

My 01 Pathfinder (104K miles, services up to date) has started running very roughly intermittently, and stalls occasionally. The check engine light has come on. When it runs rough, the CEL blinks. When it runs smoothly, the light stays on steadily. OBDII is returning these codes: P1135, P1320, and P0464. These are not in my books or my mechanic's books, and his diagnostic tech support people are having to research them, too. I had a similar thing happen to my 00 Maxima, and no one ever figured it out.Has anyone dealt with this or know what the codes mean? thanks!

P0464 = Fuel Level Sensor CircuitEither an open circuit (wiring) or the sensor is bad

P1135 = Intake Valve Timing Control, RH Bank 2

P1320 = Ignition SignalEither an open circuit (wiring) or power transistor in ignition coil is bad or condenser or crankshaft position sensor (or circuit)