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Discussion Starter · #1 ·
Hello,

Sorry if this question has been answered before but I can't find anything related to it.

My MX5 that I brought recently makes a loud rumbling noise when it comes to a stop but only sometimes not all the time.

This happens whether the car is in gear or not and if I have my clutch down, and almost sound like I'm on the biting point of the clutch even when I'm not touching it. The only way to stop it, but only for a second or two, is to rev the engine, put down the clutch or to move foward (which in that case it will stop making the noise completely). The car will make the noise when I'm stopped for a moment waiting for traffic lights but then wont make the noise again when I'm stopped by the next set of traffic lights.

The only thing that I can think of is that the engine is not happy about the ammount of air, fuel or spark it's getting at Idle. I can't figure out exactly where the noise is coming from however and I can't just make the noise happen but I will attempt to record audio when I can.

Has anyone else had a similar Issue?
 

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Discussion Starter · #6 ·
Would it not be constant if it was the Crankshaft thrust bearing or Clutch release bearing and would it be loud enough to hear clearly from far away? The exhaust shield rattling sounds pretty plausible I'll have a look when I can.
 

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Or a exhaust shield rattling at a certain resonance.

Sent from my SM-G977B using Tapatalk
My bet is this, I've been chasing a similar issue, rattle/grinding at 3k rpm when in gear only and only in over-run fuel cut. The fact it only happened in gear made me certain it was something drivetrain related.

After cutting my backbox open thinking the baffle plate had come loose in a last-ditch attempt to find this, someone asked me if I had checked the downpipe heat shield. I felt stupid. Sometimes we overlook the obvious causes.

That's not to say it isn't a bearing, bearings don't have to make noise constantly when worn but I understand your logic.
 
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