Exhaust pop sound with misfire

Good morning

Yes, it sounds like it is running lean. It will cause this type of misfire in the system.

Is this gas or diesel?

I need to know to further help you.

Roy

Good Morning, It is running on gas (octane 92). Is there a possibility of a leak? There is a pop coming from the exhaust when the ignition is off after a trip. The pop frequency reduces to 0 within 30 seconds or so gradually.

Thank you

I would start with a compression test. A burned exhaust valve will cause this issue.

https://www.2carpros.com/articles/engine-backfires-while-running

https://www.2carpros.com/articles/how-to-test-engine-compression

Beyond that I would verify timing. If the valve timing is off from a worn belt or chain, it will retard the timing and it will backfire from the exhaust.

https://www.2carpros.com/articles/how-a-timing-belt-works

Roy

Thank you for the reply. I will check the compression. That and the timing never crossed my mind because the car pulls great.

Yep, but if the timing is off, it will backfire.

Roy

Alright compression and the timing I will get checked from a shop. The guides will help me to tell them what to do. What about the pop when ignition is off?

Fuel burn off in the exhaust after turning it off.

Roy

Yes. That could be it. Thank you very much for the help. I will update here what fixed it for someone's future use.

Your welcome

Always glad to help

Roy

Hello, Still couldn't go to a mechanic. But captured a sound file of the engine.
https://we.tl/t-pOIHNNqKry (Audio file link)

Okay, sounds noisy.

When was the last time you had an overhead done?

Roy

Three years or so.

This is I am holding the phone over the engine block after fully warm up. It is not that noisy when the hood is closed. But it does sound like a diesel in the audio than a 1.5 liter gasoline. I am worried about that continuous ticking.

I would start with having an overhead done. The valves sound like they are asking for an adjustment.

Roy

Thanks. I will post an update.

Sounds like a plan.

Roy

Alright so got it tested with the mechanics. First they wanted to make sure the ignition coils are not leaking. Once that is eliminated, spark plugs were checked. Nothing wrong with that.Then cylinders and valves were cleaned by burning solvent through the PCV. After this engine became smoother and the misfire was reduced a lot. They advised to run for some time and see. If the problem doesn't go away, next is a throttle body cleanup and if not removing valve covers and deep cleaning.

Sounds like they think it is carbon build up.

Roy

I guess so. What do you think? They said if these cleaning won't do they'll get to the timing. Which you advised earlier in the thread.

Yep, I would have done the timing first to confirm it.

Roy

It turned out to be a bad coil. Misfire is gone for good and the exhaust pop is still there. Two different issues I guess. If I ignore the pop after switching off, everything is fine now.

I would not ignore it at all. It may do more damage if you ignore it.

Roy