3.5 EB Rough Idle and shudder

[Byronick87]

Hey guys,
Just bought a new 2021 XLT with the 3.5 EB
It was the last 3.5 one on the lot...
When I stepped in for the test drive, I noticed a slight shudder every 5-10 seconds - salesman said it was fine.
didn't trust him - went in and talked to the shop guy; he said it was normal for the first thousand or so miles.
is this true?

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[Twilighthan]

14k miles and still the same symptoms for me.

 

[Roady]

My 3.5 has a slight rough idle at times but nothing that concerns me too much. Many people reporting the same thing. As far as the "shudder" under heavy acceleration, yea I have that too. I don't know if I would call it a shudder but the power delivery is definitely not smooth. I've wondered sometimes if that is more related to the transmission and not the motor.

 

[Byronick87]

Thanks twilight.
I am coming from GM
A 2018 sierra with the 5.3 v8 that ran an smooth as butter.
Would have preferred a 5L but they did t have any left on the lot.
That 5.3 was GM's only saving grace.
So I guess the shudder and rough idle is normal??? The price for going with Ford??

 

[rb304]

Thanks twilight.
I am coming from GM
A 2018 sierra with the 5.3 v8 that ran an smooth as butter.
Would have preferred a 5L but they did t have any left on the lot.
That 5.3 was GM's only saving grace.
So I guess the shudder and rough idle is normal??? The price for going with Ford??

I had a 2005 Silverado with the 5.3L and 203,000 miles before buying my first Ecoboost (2013 F150, bought it used with 64,000 miles). That had many of the issues the early ones did such as a noticeable shudder during hard acceleration and flashing SES light. I attributed the issues to the previous owner not taking it in for TSB repairs or recalls, software updates, etc. I have just over 1,800 on my new F150 with the 3.5L and at times after a cold start up I do notice a rough idle, but nothing concerning and smooths out after a few seconds for me. I've experienced that with my 5.3L as well. I agree with an above poster, the shuddering while driving I believe is attributed more to the transmission than engine, especially when it is trying to find what gear it needs. I bet a software update will be released to help this issue soon - whether its from the engine or transmission. Not much helpful advice from my post, but you're not alone with the quirks you're experiencing!

 

[Byronick87]

I had a 2005 Silverado with the 5.3L and 203,000 miles before buying my first Ecoboost (2013 F150, bought it used with 64,000 miles). That had many of the issues the early ones did such as a noticeable shudder during hard acceleration and flashing SES light. I attributed the issues to the previous owner not taking it in for TSB repairs or recalls, software updates, etc. I have just over 1,800 on my new F150 with the 3.5L and at times after a cold start up I do notice a rough idle, but nothing concerning and smooths out after a few seconds for me. I've experienced that with my 5.3L as well. I agree with an above poster, the shuddering while driving I believe is attributed more to the transmission than engine, especially when it is trying to find what gear it needs. I bet a software update will be released to help this issue soon - whether its from the engine or transmission. Not much helpful advice from my post, but you're not alone with the quirks you're experiencing!

Just knowing what you said puts me at ease 10 fold!!!
Thanks for the reassurance guys!!

 

[gtotco]

My 3.5 has a slight rough idle at times but nothing that concerns me too much. Many people reporting the same thing. As far as the "shudder" under heavy acceleration, yea I have that too. I don't know if I would call it a shudder but the power delivery is definitely not smooth. I've wondered sometimes if that is more related to the transmission and not the motor.

Yeah I have had the same thing and also always assumed it was the transmission. For a transmission that reviewers have generally had good things to say about it definitely has its hiccups. Overall I think it’s pretty good but there are a number of situations where it feels a bit unrefined, mostly in lower gears and under acceleration. Highway speed I find it to be much better.

 

[rb304]

Yeah I have had the same thing and also always assumed it was the transmission. For a transmission that reviewers have generally had good things to say about it definitely has its hiccups. Overall I think it’s pretty good but there are a number of situations where it feels a bit unrefined, mostly in lower gears and under acceleration. Highway speed I find it to be much better.

Yeah I agree. I think the transmission is a solid unit, and it definitely keeps engine in its power band, but yeah, there are times where it is unrefined. To me, it feels a lot more confident in sport mode - given that it holds gears longer and isn't trying to find a gear for economy sake.

 

[DT400]

I wonder if this shudder at idle is just a lean roll condition as part of getting the best fuel economy possible.
Would be curious to see a wide band O2 reading during these condition.

Darrell

 

[Upnorth]

I just traded in my 2021 f150 ecoboost for a 2022 also with the eco boost thinking ford would fix this. I hope I wasn’t too optimistic. The dealer will let me drive it for a day. If it idles rough or stumbles I will not buy it. With so many complaints on this forum why hasn’t ford gotten the message?

 

[Dadofjax]

I've had it at two dealers both from the rough idle that shakes the entire truck. When you sit in idle check open a door and take a look at it. It's insane how much vibration mine has.

My next oil change I'll have the shutter looked at for the third time.

 

[minirx7]

Had thsi since new on mine.. I chaulked it up to it being a truck (first timer with a truck). Not only is the idle rough at times, the transmission can sometimes be very harsh and clunky.

 

[pkinneb]

With so many complaints on this forum why hasn’t ford gotten the message?

Yes there have been a lot of posts on this but Ford builds 1300 F150's a day so hard to say how wide spread this is at least in my opinion.

 

[TheGoatman]

Fill it with 93 octane

 

[Dnpbakon]

Anyone get any answers on this? My 2021 does the same damn thing. Other than the idle though the truck is flawless. 21+MPG, quiet, comfy.

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