Rough Idle

[Spaghettir101]

So when i put my dark horse in the garage and its there for about 1 week. I then start it up and starts fine, but once it gets to idle RPM (~800) the car starts to shake and has rough idle. You can hear it in the exhaust as well.
once i put it in drive or reverse, its fine no issues.
Sitting overnight then starting it and its fine.

Any idea or its normal? I PPF the whole car already lol should i get it checked by ford?

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[Carter1776]

my GT does this too, 8300 miles on the dash. Not sure what causes it but ive not had any issues with it so far so i try to ignore it.

 

[Spaghettir101]

my GT does this too, 8300 miles on the dash. Not sure what causes it but ive not had any issues with it so far so i try to ignore it.

Yeah i only have 2000 miles on it… its drives and performs fine!

 

[Carter1776]

Yeah i only have 2000 miles on it… its drives and performs fine!

i feel like it has to do with the two intakes evening out or possibly the humidity in the air. I find it happens more often when its hot and humid. These are shots in the dark obviously, just glad it hasnt caused any real issues.

 

[The Ghost]

Can you share a video clip? I posted a clip of a similar issue with mine. If you go into my profile you can find the thread. I'm curious if it's the same thing. For my car it's just the passenger side muffler with the rougher idle.

 

[135Hoser]

My DH also has an intermittent rough idle on cold start. Runs and drives alright.

 

[jimbo67]

I was having the same issue, I'm at 9500 mi. I know the car has keep alive memory, but I disconnected the battery for 30 minutes and in the last week it has not done it again? Maybe it does an idle relearn?

 

[Doug Watson]

I've had this happen a few times on my DH at only 2000 miles but then it just disappears.

 

[Spaghettir101]

I've had this happen a few times on my DH at only 2000 miles but then it just disappears.

Yeah once i drive its fine and it goes away, but if it sits for a couple days without starting it has the weird idle.

 

[Ford Motor Company]

So when i put my dark horse in the garage and its there for about 1 week. I then start it up and starts fine, but once it gets to idle RPM (~800) the car starts to shake and has rough idle. You can hear it in the exhaust as well.
once i put it in drive or reverse, its fine no issues.
Sitting overnight then starting it and its fine.

Any idea or its normal? I PPF the whole car already lol should i get it checked by ford?

Hi there! I can look into your Mustang's concern on my end. To get started, could you please send a private message over with the name/location of your local Ford dealer and your Mustang's VIN?

 

[Spaghettir101]

Update: Dealer disconnected battery and reconnected battery. The rough idle went away…

 

[jimbo67]

Update: Dealer disconnected battery and reconnected battery. The rough idle went away…

Worked for me as well.

 

[kinelisch]

Update: Dealer disconnected battery and reconnected battery. The rough idle went away…

I developed a rough idle today for about 10 minutes. Not sure what’s going on. It went away but it still lingering in my mind. Do you recommend disconnecting/reconnecting the battery?

 

[Spaghettir101]

I developed a rough idle today for about 10 minutes. Not sure what’s going on. It went away but it still lingering in my mind. Do you recommend disconnecting/reconnecting the battery?

i didnt do anything tbh, i start the car once a week if i dont use it. Once the rpms drop down into idle, i put it in D or R for a little (in the garage) then back to park. Doesnt rough idle after that.

it seems to only do it when its not started for a while and then when in normal low rpm idle

 

[goodlettjr]

Mine does it also. Doesn’t register on the RPMs though. Drive it and it goes away. Also does it if I leave the engine running and fill up. Makes me think it is a vacuum leak down or something. Nothing I am concerned about.

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