2019 Ford F-150 possible exhaust leak

My 2001 4.6 Litre Ford F-150 started making a noise that can be described as an exhaust leak. But it’s not a leak. It happens mostly at stop lights. While waiting at the light, the idle drops by about 200 RPM’s, and the noise begins. If I put the gear selector in Neutral, the noise goes away. It can also be heard in tunnels and along walls. I’ve taken it to repair shops. and that’s where they tell me it’s an exhaust leak. If it was an exhaust leak, the noise wouldn’t go away in neutral. What could this be??? Thanks

Idling at 200 rpm? It seems like that itself could cause weird noises, as the engine is just barely running. Normal warm idle rpm is usually 600-800 rpm. A small exhaust leak wouldn’t drop the idle rpm that much usually, so I think you got something else going on there OP. Any diagnostic codes?

It’s not idling at 200rpm

Idle drops by 200rpm

In neutral, the engine may sound a bit quieter because there is no load on the engine. Then shirting into gear a load is placed on the engine and the engine tilts slightly from the torque placed on it and a weak exhaust part could leak at this point. This will only get worse, the longer you wait.

I would think that the mechanic that looked cat it…or listened to it…has a better ear for this than yourself.

You hear the noise better in a tunnel or along walls because you are hearing the echo off the wall.


Thanks everyone. But I have taken it to mechanics.
If there are diagnostic codes, I am not aware of them, as the mechanic did not inform me of them.

And, no, its not idling at 200 RPM. It drops by about 200 RPM when this happens.

Yosemite, I like your reasoning on the matter. I’ll look into this a lot better with my wife helping…

Thanks again everyone.

Take care

They usually won’t inform you about the codes, b/c most customers aren’t able to interpret them. But the folks here are able to offer up some opinions based on the codes. If you ask the shop beforehand to provide a list of the diagnostic codes they’ll usually accommodate. Given the clarification on the rpms, I’m guessing along w/Yosemite above, small exhaust leak.

Careful about asking the wife to help @DwightSCook
I suggested that I tie mine to the front fender to listen for a bad wheel bearing.

She made my shampoo the living room carpet as my next household chore !!!
I should have stayed at the shop where it’s safe.


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