Ok here's my issue. One of my friends has a 03 350 with 129k on the clock. When we were driving around in it it was fine for a while then all the sudden it stalled out on us. We go it running again and limped it to his house. He had it trailered to a dealer and they read the codes and the pulled codes were for the knock sensor and the cam position sensors, and oil press. With that said the dealer called it to be catestrophic engine and ECU failure. Now the car starts up and seems to idle fine until warmed up, then once its warm as you rev it it has a knock sound. Someone said rod knock but you cant pinpoint it to a specific cylinder. When I was listening to it it sounded like a A/F knock (hence the knock sensors going off) because if the cam sensor isn't functioning properly the car wont run good at all. Now upon a cold start the oil pressure goes up to where its supposed to but as it warms up it drops and if you shut the car off and restart it the oil gauge will read 0 psi. To me that sounds like a bad sensor in itself. now anyone with any insight on this issue please help because were trying to get the car back up to running good again.

 

A friend of mine had similar problems with his G35. Infiniti replaced the ECU, throttle body and other parts and he still had the problem. He eventually figured out his car had no oil in it. Not sure if it's the same problem but sounds similar to his.

 

If the engine is knocking, and the oil pressure gauge are reading low (or zero in this case)... I doubt it's the sensor. It sounds like low oil.

There's too many variables to come anywhere close to an accurate diagnosis based on the info you've given.

 

Knock sensors can go off for ANY sound that's in the rough frequency range that it listens for. Many times it's true knock (like it's designed to pick up, A/F-wise). Mechanical sounds can also be picked up as "knock."

Can't speculate much more without hearing it.

 

Oil level is full, all fluids are topped off. That was one of the first things I had checked out on it. The sound is somewhat hollow and as the car warms up to temp it gets louder, now as you rev it it doesn't really get much louder, its just a constant hollow sound that seems like its coming from the heads (but no pinpointed cylinder)

 

I don't do "my friend" threads. Its against my religion.