Rough idle from the ICE when cold

[Hans Moleman]

Does anyone truck have rough idle with the gas engine when cold?

Mine engine seems to have a rough idle when the it is cold. At 1000 rpm there is a lot of vibration/resonance/rumbling which causes the dash and skid plate or heat shields to rattle.

Once the engine is warm it’s pretty smooth, if hasn’t switched over to electric mode..

No service engine light and Forscan doesn’t show any DTC’s.

Is this just the nature of this engine? I wonder if the regular 3.5 ecoboost is also like this.

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[22Platinum]

I have rough idle (500rpm) on occasion though mostly warm, and I have shuddering/surging around 1000RPM in high gears at low load (40mph, 9th-ish gear).

I think I read that 3.5s have had shaky idles, something like low oil pressure; was true on earlier models.

 

[dbtgt]

Does anyone truck have rough idle with the gas engine when cold?

Mine engine seems to have a rough idle when the it is cold. At 1000 rpm there is a lot of vibration/resonance which causes the dash and skid plate or heat shields to rattle.

Once the engine is warm it’s pretty smooth, if hasn’t switched over to electric mode..

No service engine light and Forscan doesn’t show any DTC’s.

Is this just the nature of this engine? I wonder if the regular 3.5 ecoboost is also like this.

Intermittent rough idle is a common characteristic of the 3.5L Ecoboost engine. Sounds like it carries over to the 3.5L Powerboost engine.

 

[Hans Moleman]

I have rough idle (500rpm) on occasion though mostly warm, and I have shuddering/surging around 1000RPM in high gears at low load (40mph, 9th-ish gear).

I think I read that 3.5s have had shaky idles, something like low oil pressure; was true on earlier models.

Intermittent rough idle is a common characteristic of the 3.5L Ecoboost engine. Sounds like it carries over to the 3.5L Powerboost engine.

that’s good to know. I hate to have the dealer to start replacing parts and potentially cause other problems

 

[dbtgt]

that’s good to know. I hate to have the dealer to start replacing parts and potentially cause other problems

I noticed it on the first drive of my 2021 EB when it had 21 miles on it.
Still does it at 49,500...

 

[Gord0]

The 3.5 Ecoboost is known to occasionally have a rough idle. My 2013 had it from when I got it till over 200k miles. My 21 has it as well. I replace spark plugs a LOT earlier than most (30-50k) and gap to .028". That helps a lot.

 

[Samson16]

I also experience an occasional "rougher than normal" idle. I think the module that controls and decides the air/fuel ratio, ignition timing, and valves is confused a bit somehow when that occurs.

Captain Obvious reporting for duty

 

[Aim64]

I noticed it on the first drive of my 2021 EB when it had 21 miles on it.
Still does it at 49,500...

Same here with my 21 Platty 16,000 miles on it

 

[KirkBay]

I noticed it on the first drive of my 2021 EB when it had 21 miles on it.
Still does it at 49,500...

As does my 21 PB with 105K on it. Some days more than others.

 

[Hans Moleman]

I looked up some more threads and it looks like it’s normal like everyone mentioned. In one thread one person even had his engine replaced which caused other issues.

https://www.f150gen14.com/forum/thr...oost-v6-rough-idle-and-cabin-vibration.14074/


https://www.f150gen14.com/forum/threads/2021-f150-xlt-3-5l-ecoboost-idle-“shudder”.7692/page-2#post-288971


The strongest vibration and rumbling happen at exactly 1000 rpm for my engine.

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