Low frequency boom noise from engine/exhaust

[zhaninsx]

I noticed a low frequency boom noise (like a very deep bass boom) coming from the engine/exhaust yesterday and again today when I took my 1998 NSX for a drive. Details are:

• Frequency is around 2-4 booms per second, no real pattern as far as I can tell.
• Only happens when engine has warmed up to operating temperature (no noise when engine is cold).
• Noise is loud enough to be heard from inside the car with the targa top off.
• I only drive my NSX about once a month, approx 10-20 miles each time.
• Last fuel fill was 3+ months ago.
• 46k miles on the clock.
• Last oil change was about 1 year ago.
• Car is unmodified other than an oil based air filter.
• No check engine lights etc and car drives and accelerates fine.

Does any one have any ideas what could be causing this?

 

[B2FiNiTY]

Check for exhaust leaks.

 

[JD Cross]

Check for exhaust leaks.

Exhaust leaks is a good area to check.
I've also had booming noises which turned out to be tire noise and was more noisier on some road surfaces.

 

[zhaninsx]

Thanks for the feedback. Are exhaust leaks generally fixable or is the only solution replacement of the offending part?

 

[B2FiNiTY]

Exhaust leaks are typically very easy to fix. Just replace the associated gasket which has worn out typically due to age.

 

[docjohn]

Exhaust leaks is a good area to check.
I've also had booming noises which turned out to be tire noise and was more noisier on some road surfaces.

yep tires especially when worn

 

[brettowen]

+1 on tires. Especially if they're near end of life (miles or age).