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Exhaust note from front of car?

For 8 or so months now, I’ve noticed low idle on startup, both with a warm or cold engine.

About 6 weeks ago I noted some slight pinging from the engine when driving. I upped the octane of the gas I buy and the pinging stopped, so I assumed it was engine knocking.

Then about 3 or 4 weeks ago I’ve started to notice an exhaust sound from the front of the car when under heavy throttle. No noise while in gear and coasting, or in neutral, but when the pedal is buried (or more than half depressed), I hear a noticeably loud sound, that sounds much like the back of a motorcycle.

Any chance the three are related, and what’s the potential concern? So far I have not noticed any change in performance or mileage (mileage may have gone up a few percent, but that might be more highway driving or the higher octane).

Well, the car is about 10 years old, so it could be a heat shield or a hole in the exhaust pipe somewhere

Could even be an exhaust manifold problem. Chances are you have more than one problem,but start simple and work your way up. You have a leak in the exhaust system, fix that and go on from there.

With the car cold, get someone to hold a wadded up rag over the end of the exhaust pipe. It’ll take quite a while for things back there to warm up, so there is no risk of a burn. If they can’t hold the rag in place, it’s unlikely that you have an exhaust leak. If they can, you should be able to hear the leak much better and to locate it. You can check by waving your hand around near where you think the exhaust is leaking. You’ll find a stream of (possibly very) hot air where the leak is. Watch out for moving and hot parts when doing that.