I know you guys dealt with alot of knocking problems, I did a search but couldn't find anything similar. Recently my car developed a regular hollow knocking sound. It can only be heard at idle in a quet place. The weird thing is that its barely audible, unless the light and foglights are on. Once I switch them on then I can hear it, good inside the car. I have a 98 GXE 5spd with 52k miles. I tries using a different gas(Amoco), that didn't help. I have also changed the oil recently.

 

did u check alternator? also your car is still under 60k warranty why not take her into nissan dealership for free repair?

 

Try to use Daniel B. Martins rubber hose trick to isolate the noise. Take a small section of tubing and place one end in your ear, use the other, free end, to roam around the engine bay until you come across the noise. Be careful of moving parts, and the fan can start up at any time!! Try this and repost what you observe. It sounds odd that it is affected by your fog lights, unless you wired up some super heavy duty, pulling a lot of amps lights. Good luck.

 

I bought it used from a used car dealer. I don't think it has waranty. Could the alternator be making the knocking sound? I don't see how?

 

I forgot to mention that I checked the ECU codes and I came up with 05 05 wich is supposed to mean everything is fine, if I'm correct.

 

does not matter, any nissan dealer will honor 3 year 60k miles factory warranty. just take car there and they will do the work

 

Maximas come with a 36 month, 36,000 mile basic warranty. Or at least, mine did.

 

Diagnostic Trouble Code 0505 means No Trouble Found. However, that does not mean there is no problem. The Engine Control Module does not test everything in the car. To give an absurd example, your Maxima could be disabled because of an empty fuel tank and four flat tires but the ECM would still say "0505".

Please use the rubber tube sound-locating technique and post your findings on this thread.

 

It is important to identify the source of the noise. A four-foot length
of small diameter rubber vacuum hose will help you do this. You can buy
the hose in any auto parts store. They typically sell it in bulk for about
US$0.80 per foot. Start the engine and let it idle. Put one end of the
hose in your ear and the other end near any suspected source of noise.
The engine compartment presents a cacophony of sound. The benefit
of the hose is that it isolates the sound from one specific area. Work safely!
Avoid contact with any moving parts!

You may find it interesting to explore the sounds of your engine with this
inexpensive tool. Each moving part has its own characteristic sound. For
example, listen to the muted clicking of the fuel injectors. They should
all sound alike. If you find one with a different sound (or no sound at
all) you have found a problem.

The dealer's service department is equipped with high-tech diagnostic
instruments. These are wonderful devices but they are expensive and the
dealer has to recover his cost by charging you for diagnostic time.
Sometimes the home mechanic can do legitimate diagnostic work with
nothing more than a rubber tube.