Rough Idle / Miss. Only At Idle In Drive
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Cross-Country
Joined: Nov 2019
Posts: 72
Likes: 9
From: San Francisco
Rough Idle / Miss. Only At Idle In Drive
Hi All,
I'm having an issue with my 2001 6.8L 2WD. I have a random rough idle or miss but only when it's idling in drive. In neutral or park it goes away. Doesn't miss while driving or slowing down.
Plugs and boots only have about 7K miles on them.
Thanks
I'm having an issue with my 2001 6.8L 2WD. I have a random rough idle or miss but only when it's idling in drive. In neutral or park it goes away. Doesn't miss while driving or slowing down.
Plugs and boots only have about 7K miles on them.
Thanks
Cross-Country
Joined: Feb 2026
Posts: 52
Likes: 20
have you checked for codes yet? Look at your fuel trims in live data. Might have a vacuum leak which would be shown in your fuel trims.
Cross-Country
Joined: Feb 2026
Posts: 52
Likes: 20
fuel trim is the ecu making micro adjustments to the air fuel ratio based on O2 sensor feedback. So if you have a vacuum leak you’re getting a lot of unmeasured air into the engine (the MAF sensor isn’t reading air that’s being sucked in through the leak). That means the ecu will add fuel in an attempt to get the AF ratio into spec since there’s air in the exhaust that it wasn’t aware of until it was too late.
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TCK
1997 - 2006 Expedition & Navigator
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Sep 2, 2024 12:47 AM
