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Rough Idle When A/C On

mcfarlrm

mcfarlrm

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Yesterday I noticed a rough idle while sitting at a red light. The A/C was on at the time and when I turned it off the idle returned to normal. About 20 min later, with the A/C back on, I gave it about half throttle from a stop and hesitated to accelerate and jolted at about 4500 RPM. Has anyone else experienced this issue? Looks like there is a TSB to address this issue to reprogram the PCM. I had a recommended fuel injection service done about a week ago and hoping that they didn't screw anything up with the throttle body, fuel rails, injectors, etc.
 

T

TXCarbonized

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Did you ever get this figured out? My 2022 seems to idle rough when the AC is on too. When I turn the AC off, it's perfectly smooth.
 

OP
mcfarlrm

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Issue comes and goes. Of course, dealership/service dept said they couldn't find anything wrong.
 

T

TMac

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This is most likely not a big deal. When you're at idle and the AC pump is engaged, it places a load on the engine. Does the RPM drop and not recover? Does the engine "smooth" out after a bit of time? Did they address the TSB?
 

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mcfarlrm

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RPM's would drop and recover and engine would stumble. Haven't really noticed it lately so not concerned anymore.
 

Hassa

Hassa

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mcfarlrm said:
Yesterday I noticed a rough idle while sitting at a red light. The A/C was on at the time and when I turned it off the idle returned to normal. About 20 min later, with the A/C back on, I gave it about half throttle from a stop and hesitated to accelerate and jolted at about 4500 RPM. Has anyone else experienced this issue? Looks like there is a TSB to address this issue to reprogram the PCM. I had a recommended fuel injection service done about a week ago and hoping that they didn't screw anything up with the throttle body, fuel rails, injectors, etc.
Click to expand...
The TSB that fixes this issue is TSB 20-2405. Print it out and bring to the dealer with the complaint of a rough idle with AC on. Reprograming the PCM fixes this issue. It's also the fix for Safety Recall 22S27, so the dealer has two reasons to update the module.
 

L

Lightning Struck

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Hassa said:
The TSB that fixes this issue is TSB 20-2405. Print it out and bring to the dealer with the complaint of a rough idle with AC on. Reprograming the PCM fixes this issue. It's also the fix for Safety Recall 22S27, so the dealer has two reasons to update the module.
Click to expand...
I suppose this would pose an issue if you have a tune though.
 

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mcfarlrm

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AC issue is back again causing engine to stumble at a complete stop. Issue goes away when in park, neutral and when AC button is turned off. Having Ford look into it once I take it back in to get my transfer case repaired. This SUV has had more problems than any other vehicle I have ever owned.
 

hbalek

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mcfarlrm said:
AC issue is back again causing engine to stumble at a complete stop. Issue goes away when in park, neutral and when AC button is turned off. Having Ford look into it once I take it back in to get my transfer case repaired. This SUV has had more problems than any other vehicle I have ever owned.
Click to expand...
That reminds me of my 1983 Ford LTD and 1985 Tempo! My ST hasn't done this...Knock on wood!
 

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