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Noise on acceleration

car makes a noise like a jangling bracelet when I press accelerator. Doesn’t make noise while idling.

The way that one person describes a noise can be totally different from the way that someone else describes the same sound, and that can make it difficult to nail down the actual problem causing the noise. With all of that being said, the first thing that I would want to eliminate as a possibility is “ping” or “knock”.

When an engine is pinging, most folks describe the noise as sounding like pebbles rattling around in a tin can when the can is shaken. Is it possible that this description applies to your situation? If it does, then I would suggest that you get this attended to right away, as internal damage is caused by ongoing pinging.

What causes pinging?
It is the result of uneven combustion of the gasoline in the cylinders, and that can be the result of the following:

Using regular gas when premium is required
An engine that is running too hot
An EGR valve that is stuck
A knock sensor that is no longer working
Failure to replace spark plugs on schedule
Excessive carbon build-up inside the combustion chambers

So–the first thing that I would suggest is to check your Owner’s Manual to see if it specifies “premium gas required”. If it does state that, are you using premium gas? If you are not using this higher octane gas, start filling up the tank right away with premium fuel that will control the rate of combustion better than regular gas.

If I recall correctly, the Nissan Maxima of that era did require premium gas, and your Infiniti i35 is mechanically identical to the Nissan Maxima, with the only real differences being the grill, the tail lights, and the upholstery. So–please be sure to check the manual carefully in order to determine if premium gas is required.

If you are already using premium gas, then I would suggest having your mechanic check/clean the EGR valve, and replace the spark plugs if it has been more than 60k miles since they were replaced. And, while he is under the hood, you should have him check the functioning of the knock sensor also. When the knock sensor is working properly, it retards the engine timing if pinging is detected. If it is not functioning, then the timing will not be corrected, and damage to the engine can result.

The only other thing that comes to mind is…possibly…a loose or bent heat shield on the exhaust system. When these thin sheet metal parts become damaged, it is very common for them to make an annoying racket, but only under certain conditions, or at specific engine RPMs. This situation is not at all dangerous to the car, but it can be incredibly annoying. A couple of minutes underneath the car while it is on a lift can allow your mechanic to see if a bad heat shield is the problem.