John Jeffries Posted December 15, 2022 Report Share Posted December 15, 2022 has anyone else experienced a bad drone at idle? Wife's 2008 MKX started doing this and it does not matter if in park, gear or neutral. Sound seems to come from everywhere and goes quite after you step on gas. Quote Link to comment Share on other sites More sharing options...
Cosmos36 Posted December 16, 2022 Report Share Posted December 16, 2022 I would suspect that some function (or functions) of the Engine Control Unit/Module (ECU aka ECM) affecting ignition timing, air-fuel mixture, variable valve timing, etc may be influencing engine sounds, especially during idling prior to engine warmup. Quote Link to comment Share on other sites More sharing options...
John Jeffries Posted December 16, 2022 Author Report Share Posted December 16, 2022 it sounds very much like an exhaust drone. Not like a leak but like a loud performance muffler with a subtle almost bass speaker vibration and it leaves after coming 100 RPM off idle Quote Link to comment Share on other sites More sharing options...
Cosmos36 Posted December 17, 2022 Report Share Posted December 17, 2022 Your description closely describes the 'drone' commonly experienced by owners of recent vintage MKX owners (mine with the 2.7 turbo) when a cold engine is first fired off and running for the next minute or two until the ECM adjusts fuel mixtures & engine timing. It's all intentional to address emissions at startup, but some owners have admitted to being embarrassed when they were showing/demonstrating their new MKXs. Perhaps your 3.7 ECM is mimicking the more recent vintage MKXs. Quote Link to comment Share on other sites More sharing options...
enigma-2 Posted December 30, 2022 Report Share Posted December 30, 2022 (edited) Have you changed anything in the exhaust system? A droning sound is common in aftermarket exhaust systems, especially where the cats have been removed or gutted. Any chance your cats have burned open? Edited December 30, 2022 by enigma-2 Quote Link to comment Share on other sites More sharing options...
John Jeffries Posted December 30, 2022 Author Report Share Posted December 30, 2022 11 hours ago, enigma-2 said: Have you changed anything in the exhaust system? A droning sound is common in aftermarket exhaust systems, especially where the cats have been removed or gutted. Any chance your cats have burned open? No changes, factory equipment all intact and working Quote Link to comment Share on other sites More sharing options...
John Jeffries Posted December 30, 2022 Author Report Share Posted December 30, 2022 I got to drive MKX over holiday and noticed the idle seems low around 500 RPM. Just the slightest increase in engine speed and the noise goes away. Take the engine to 600-700 and buzz leaves. Quote Link to comment Share on other sites More sharing options...
enigma-2 Posted December 31, 2022 Report Share Posted December 31, 2022 Air idle control, maybe? Leaking hose? Quote Link to comment Share on other sites More sharing options...
John Jeffries Posted December 31, 2022 Author Report Share Posted December 31, 2022 15 hours ago, enigma-2 said: Air idle control, maybe? Leaking hose? I wondered about that but a code scan did not show mixture lean. Back in the carburetor days I would have just cranked the idle screw a turn or two. That does not work on modern computer infused vehicles Quote Link to comment Share on other sites More sharing options...
enigma-2 Posted December 20, 2024 Report Share Posted December 20, 2024 You have probably already found the cause (just got back on this forum) but low power steering fluid can cause a drone at idle to start up. If low, check for leaks. Quote Link to comment Share on other sites More sharing options...
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