2008 G37s Coupe. Stock piping megan catback. No power loss low end. No noise coming from engine bay or intake arm. Cant feel vibration from in the car. Noise coming directly under car. What the FFFFFFFFF is this!!! Only happens at 1.5 - 2K rpm in parked or driving.



IMG_0633.MOV - YouTube

 

Sounds like engine knocking, but from under the car.

I would check all the hangers and make sure they're where they're supposed to be. One of them might be out and is vibrating against the frame.

Also, might wanna have someone rev the engine with someone else underneath trying to find out where it's coming from.

Whatever it is, doesn't sound good.

 

I don't think that's rod knock. Sounds like some accessory (belt driven) is hitting something.

Rod knock is usually more metallic sounding.

 

Any more info would help. I am going to my mechanic today to have him check this out

 

i have the exact same problem with my g since i got it! i went to the dealership at least 4-5 time for this they were never able to replicate the problem. they said the exhaust line and the muffler was okay. But once in a while, i get that sound but when i rev it up to 3k rpm it goes aways. Its only doing it after driving the car for like 30min,stop it and then start it again after 15min. If you find what is the problem, let me know!

 

Found the problem! Took it to a shop today and it was my catalytic converters. What is the warranty for our exhaust? Will infiniti replace them if I have axel back exhaust?

 

Exhaust is covered under the 4year/60k mile basic warranty. Only if it starts to corrode can you get them to replace it under the corrosion warranty which is 8 years / unlimited mileage.

 

i got the same noise, taking it in on wednesday

 

cats? yikes.

 

weird...I was gonna suggest heat shield (notorious for rattling) but after hearing it that wasnt it. Cats huh?

 

yeah bad cat... they only are replacing one and not the pair is this a problem?

 

the other cat is also bad now... fml.

 

I too had the exact same noise and took it into the dealer a few months back and they replaced the driver's side cat. Apparently the honeycomb material inside broke free and was rattling around - sounds like a run of crappy cats. It was covered under the base warranty only. I have a completely stock OEM exhaust btw.

 

Had the same thing happen a while ago when I installed my sc. It was the cats. Replaced with tp and sounded fine