I have a 2021 xlt 3.5 and I’m having a rough idle problem is any one else having this problem

 

How rough an idle? Most engines idle are not super smooth and quiet when cold. My 3.5 is very smooth and quiet once warmed up. You don't even know its running.

 

I have experienced the same roughness once or twice now. I've only had my truck a week though. To be honest, my 2016 did it as well. I have noticed that if I am parked in a spot where the nose of the truck is lower than the tail, the chance of it happening is much higher. I have also noticed that it doesn't go away until it is driven. It will smooth out when RPM is added, but go back to rough once throttle input is removed. Personally, I'm not worried about it. My 2016 had 156,000 miles on it and didn't have any issues with running or driving otherwise.

 

the 3.5 is a crazy smooth running engine. does it shake or vibrate?

 

like my seat is kinda shaking rough this is my first Ford so I was just curious is it normal

 

shake

 

thats exactly what I did and same outcome

 

Hi,
Just purchased my F150 3.5 XLT few days ago,
and also had a rough idle happen few times.
Don’t know yet if related to a warm engine or cold engine.

New Ford owner and really thought the 3.5L was the best engine to get. So a little bit surprised so far.
Will keep a eye on this going forward to see if this
stays the same or gets worse/better.

 

My 2018 didn't have this issue.

Put 30k on it and never had a single hiccup.

2021 xlt has rough idle 30% of the time.

Of course Ford says nothing they can do until it rhowa a code.

Frustrated.

 

Just curious, what octane fuel do you use? As a test, try 91/93 in the next tank, whatever the highest grade you can get, and see if it runs smoother.