AC causing fluctuating AFR and rough idle

[Loucas]

Greetings. I posted over in 6g but didn't have much luck so I thought I'd post here. This started a couple of days ago while out driving. I turned on the AC and the AFR started jumping around and idle started going from 700 to 500 and back up again. Anyone have any idea what could be going on? Battery issue maybe? Vacuum leak? It goes away if I turn off the AC.

This has happened before (several months back) and then it disappeared until this weekend. Maybe it's time to buy a new battery?

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[Zig]

Compressor

 

[Loucas]

Thanks for your reply. I'll make sure to mention it to the service rep when I take it in.

 

[jboogie1289]

Sorry …. “AFR”??

 

[ShaZadam698]

Sorry …. “AFR”??

Air Fuel Ratio

 

[Loucas]

Right, sorry, the Air/Fuel Ratio. From what I've observed with my car, under normal circumstances, the AFR settles down at around 13.9/14.1 at idle. But when the rough idle starts, the AFR moves quickly up and down, along with the engine idle speed moving between 400 and 700 RPM, cycling up and down. And this happens when I turn on the AC. It feels like it is going drop below 400 RPM and stall. If I turn off the AC, it all goes back to normal. I plan to take the car in for its 30k mile service (if there is such a thing) and have it checked out.

 

[Ford Motor Company]

Greetings. I posted over in 6g but didn't have much luck so I thought I'd post here. This started a couple of days ago while out driving. I turned on the AC and the AFR started jumping around and idle started going from 700 to 500 and back up again. Anyone have any idea what could be going on? Battery issue maybe? Vacuum leak? It goes away if I turn off the AC.

This has happened before (several months back) and then it disappeared until this weekend. Maybe it's time to buy a new battery?

Hello, I would like to take a further look into your rough idle concerns. Could you please send us a message with your VIN and mileage?

 

[Loucas]

Hello, I would like to take a further look into your rough idle concerns. Could you please send us a message with your VIN and mileage?

Thank you. Yes I can. Will send it over in a minute.

 

[jimbo67]

Rough idle with the Ac on with humidity. Sounds like a update to me. Same happens here when I head to work in the morning. Then goes away, maybe a dual Maf thing? Idk but sure it won't get fixed soon.

 

[Loucas]

Rough idle with the Ac on with humidity. Sounds like a update to me. Same happens here when I head to work in the morning. Then goes away, maybe a dual Maf thing? Idk but sure it won't get fixed soon.

Thanks. I tested it out this morning and it worked normally.

 

[jboogie1289]

Air Fuel Ratio

Ahhhh, ok. Thank you.

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