So I'm having some problems with my 2010 Fit Sport, looking to get some diagnosis from those with more experience than me. Here are the issues in as much detail as I can give:

The problem has been around for a while, but mechanic only recently decided it was a problem. My first red flag that the problem might not actually be that big a deal.

- On startup, the car makes a very rapid, high-pitched knocking/rattling sound for about half a second and then stops.
- The sound returns between ~2500rpm through ~3500 rpm, does not continue as RPM's increase, but returns when I let off the gas. (Sound does not continue while gas is applied, only when the gas pedal is released. Exception for that narrow band of RPM)
- The sound seems to be coming from the engine area, but is not consistent with Rod Knock audio I have heard. (for one, it is WAY more rapid, and sounds more like when you hold a piece of vibrating metal up to metal that isn't vibrating. Much more tinny)
- I think it is the Catalytic Converter Heat Shield rattling around based on audio from another video, but it IS fairly loud compared to some videos I've seen. (Granted, this may be an audio quality issue.)
- It is loud enough to be audible from inside the car if the radio is off.

I mostly want to know if my prediction is right before I decide to worry less about it. Honestly, this same shop hasn't had the best track record for accurately telling me my needs. (has told me, for instance, that my radiator hoses needed to be replaced when they were just fine.)

If I really need to provide audio, I can make an attempt. It may take me some time, though.

 

Couple of questions.....

1. Have you checked your oil & is it where it should be?

2. How many miles on your Fit?

From your description it sure does sound like a rattling heat shield. I would not assume that is it & ignore. You need to find out if this is the cause. Not to worry you, but it could be something else.

I'd stop using your mechanic, he seems to be more interested in your wallet than your car. Find a shop who speaks Honda & have them do a diagnosis.

Good luck.

 

I second the above recommendations!

Probably a heat shield, but find out for sure. Use a new shop if necessary.