Light shudder at idle

[blwnsmoke]

For anyone who has their ST, does anyone feel a light shudder at idle? It's not a constant vibration nor a miss with the engine firing.. but it is definitely an idle shudder. It's almost like you feel the AC kick on which puts strain on the engine quickly before it recovers.

It isnt the AC, I see no rpm movement (should use forscan to monitor the actual rpm in numbers). I noticed it since the day I picked it up.. the idle definitely isnt smooth like butter.

Just curious if anyone else feels it when idling (it is obvious when sitting at a red light).

And it is definitely the engine I am feeling. The more I think about it, I'd say picture a dog laying down and is cold. You see their skin quickly shudder and then pause for a couple seconds.. then do it again. It's that type of feeling.. light but annoying.

 

[dstewart51]

I cant say I ever noticed that.

 

[Rossi6998]

Me either...

 

[cpainter3]

Me three.

 

[RayoVac]

For anyone who has their ST, does anyone feel a light shudder at idle? It's not a constant vibration nor a miss with the engine firing.. but it is definitely an idle shudder. It's almost like you feel the AC kick on which puts strain on the engine quickly before it recovers.

It isnt the AC, I see no rpm movement (should use forscan to monitor the actual rpm in numbers). I noticed it since the day I picked it up.. the idle definitely isnt smooth like butter.

Just curious if anyone else feels it when idling (it is obvious when sitting at a red light).

And it is definitely the engine I am feeling. The more I think about it, I'd say picture a dog laying down and is cold. You see their skin quickly shudder and then pause for a couple seconds.. then do it again. It's that type of feeling.. light but annoying.

So I test drove a ST at my local dealer on Thursday of last week. Drove it a few miles, about 10 minutes. I noticed as we turned off a highway and pulled over for me to mess with menus and such... a subtle vibration at idle. I would almost call it a Lope... ya know tune lope, engine lope.. think old school V8. It was only noticeable at idle. We pulled it up the the service door when we were done with it. When the service guys came out to check it, it had stopped doing it.

Is this seem similar at all to what yours is doing?

 

[Kanary]

First time poster here...my ST is in production limbo and is expected in the next few weeks.

I have a little input on this that could be part of what you’re feeling. I’ve daily driven a focus ST for 6 years and experience a very similar shudder. I spoke with a friend of mine who is a tuner of focuses. The gist of it is that for these Hi-Po ecoboost engines going into the STs, Raptors, etc., the ecu is designed to hunt for power by determining fuel grade. The ecu will continuously monitor the octane level by advancing timing until the knock sensor picks up knock. Then the ecu rapidly retards timing and the process starts all over again.

My understanding is that can cause shudders at idle. The advantage is that the ST engines effectively have two power ratings one at 87 octane and one at 93. Apparently most modern engines will hunt for timing based on the octane level and fuel quality, but in high horsepower performance applications, the concept is more aggressively applied.

I’m curious if anyone with a platinum notices the same as the tuning isn’t as aggressive as the ST.

 

[Rossi6998]

Interesting...

 

[cpainter3]

Since I currently have a tankful of 93, I’ll consider a little shuddering now and then as a good thing

 

[Forddealz]

Since I currently have a tankful of 93, I’ll consider a little shuddering now and then as a good thing

When I get mine, i will try to use 93 Octane fuel.

 

[SeattleST]

I too experienced this today twice at traffic lights. It’s almost like the idle was too low for a few seconds. I’m still on my 1st tank of gas which I’m sure the dealer put in 87 so we’ll see if that changes with 93.

 

[blwnsmoke]

I won't be able to do it now till this weekend but I'll hook up my OBDII adapter and monitor rpms.

 

[rpmgolfs]

Do these Fords have the gas saving measures that shut down several cylinders when at a stop light for example?

 

[peterk9]

They have Stop and Go technology. It does more than deactivate several cylinders. It shuts the engine down.

Peter

 

[Wilkinda65]

Do these Fords have the gas saving measures that shut down several cylinders when at a stop light for example?

It shuts down all the cylinders

 

[blwnsmoke]

So the Ex no longer does this shaking/vibrating any longer. Not sure why it did it but seems it resolved itself.

 

[Forddealz]

So the Ex no longer does this shaking/vibrating any longer. Not sure why it did it but seems it resolved itself.

What about that noise that you were hearing while driving out of your passenger side? I can't believe Ford did not test drive this vehicle with windows opened.

 

[blwnsmoke]

Still constant. Still haven't visited the dealer on anything. We just turned 2,200 miles and we took a day trip today and never felt it. Asked my wife and she said the same thing, she doesn't notice it any more.

 

[cpainter3]

Still constant. Still haven't visited the dealer on anything. We just turned 2,200 miles and we took a day trip today and never felt it. Asked my wife and she said the same thing, she doesn't notice it any more.

I love it when things fix themselves.