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Discussion Starter #1
Looking to see if anyone has thus issue when sitting idling. Usually when sitting it idles about approx. 700 revs. However, I notice when sitting sometimes it nearly stalls. It'll be sitting at 700 revs, then suddenly drop down to 400/450 then jump back up to 700, and will repeat this back to back then to back to idling at 700 fine. When the revs drop though there is a small shudder as if it's stalling.

Also, not sure if this is related. But sometimes after a long run when I pull into the parking lot, the idle revs will sit at 1500 for ages before dropping down to 700ish again.

Anyone any ideas? Ford week to think all is well.
 

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How long has it been doing this, and when was the HG done? What mods?

Welcome to the forum!
 

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Have you just had the head gasket replaced or any work done to it?
 

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Discussion Starter #5
Thanks guys!

The car is new to me, and I only noticed it after doing about a thousand miles in it. I picked it up with 8k miles on it, and I'm now at 13k. It does seem to he doing it less these days, but still does it. It was made in July 2017 so not sure if it had the recall or not. According to Ford, it did have a recall done in May 2018 but they couldn't tell what it was. From looking in the engine bay, it does look like it has the correct gasket (has that ring at the side of the block).

Car is totally standard except some visual stuff (mountune mud flaps)
 

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Excluding potential problems and catalyst warm up scenario on cold starts, the car will not have a perfect smooth idle.
It will move slightly up and down. The standard range is between 800 and 850 rpm.
The quality of fuel and how clean the injectors are is also a factor.
 

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Discussion Starter #7
Excluding potential problems and catalyst warm up scenario on cold starts, the car will not have a perfect smooth idle.
It will move slightly up and down. The standard range is between 800 and 850 rpm.
The quality of fuel and how clean the injectors are is also a factor.
It usually does this more after a long run to be honest. Will roll up to traffic lights and stop then it'll almost fall over itself due to the revs dropping too far
 

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Discussion Starter #9
I'm suspecting a timing issue, but ford say all is fine, irritatingly
 

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I swapped plugs for 1 step colder iridium NGKs and that normalized my idle quite a bit. Are you still on the original spark plugs?

Sent from my SM-N950U using Tapatalk
 

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Discussion Starter #11
I swapped plugs for 1 step colder iridium NGKs and that normalized my idle quite a bit. Are you still on the original spark plugs?

Sent from my SM-N950U using Tapatalk
I'm still on OEM spark plugs yes. Had them changed as part of the service back in march for new ford OEM ones
 

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Take a video of it with your phone, then show to the dealer, insist on having the pressure test done for the HG fix a second time. Have a read:

There's a good chance your car needs the HG fixed again.
 

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I'm still on OEM spark plugs yes. Had them changed as part of the service back in march for new ford OEM ones
you should pull them to see if the ford mechanic actually gapped them correctly
 
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Discussion Starter #14
I'm wondering here, any way this could be a cam timing issue? Only seems to be an issue at low revs, after revs exceed 1k it runs flawless.

Except that sometimes it idles at 1500 even after a long run. Could there be an issue with the throttle control system?
 

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Discussion Starter #15
Also to add, sometimes the car is leapfroggy/jerk when at low revs in first and second gear. Revs will bounce around a good bit if little to no accelerator input is on. Fuel pump/sensor issue?
 

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Hmm, I don’t have jerkiness in low gear but mine does idle roughly sometimes, exactly as you describe.

Mine is stock with 40k miles, has done well at 10 track days and still pulls as hard as I remember new. I’m not worrying about it...
 

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Discussion Starter #18
Will your revs go all the way down to 450 before going back up?
 

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Discussion Starter #19
Hmm, I don’t have jerkiness in low gear but mine does idle roughly sometimes, exactly as you describe.

Mine is stock with 40k miles, has done well at 10 track days and still pulls as hard as I remember new. I’m not worrying about it...
Will your revs go all the way down to 450 before going back up?
 

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Will your revs go all the way down to 450 before going back up?
I haven’t watched how low they go, but it does sometimes sound like it might stall, then revs pop up higher to recover.

Still probably not a bad idea to catch it on video and show your dealer just to document, but it might be normal...
 
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