hi, i am having the problem after had a long journey. my exhaust making loud rattling noise when accelerated. this is followed by weird tachometer needle, it takes longer to return to idle. this is JDM ZC 16 sohc engine. i opened up the hood and see no missing parts. also visually checked the exhaust system there seem nothing look like a leakage.

is this has something to do with the exhaust system?
or is it something not right with the internal component of the engine? watch the video i recorded

 

Any CEL codes?

Any performance issues?

Have you crawled under the car to pinpoint the noise?

 

Ya need to physically check your exhaust system. Rattling noise sounds like your cat conv. heat shield came loose.
I dont see nothing wrong with your tach.
When returning back to idle, ya mean rpms drop slowly or returning back to 700 +-50
https://honda-tech.com/honda-crx-ef-...hpots-2525374/
If ya want your revs to drop down/up a little faster, you can install a lighter flywheel.

 

yes. normally it will return back faster. not slowing down at 1000rpm. i just uploaded new video you can hear it noisier when I open up the hood.

 

RonJ. no check engine light come out. i didn't notice any changes in performance. not yet crawling. will do it when i'm free

 

Sounds like a race car.....keep it!! But no seriously, there's a leak somewhere. Crack in the header perhaps?

 

Clean the throttle body, and adjust the throttle cable to have a little slack.

 

Pinpoint the noise. The leak (which sounds like what's going on) will cause this problem. Throws off the o2 sensors, but might not throw a code for a while.