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Idle vibration

21K views 21 replies 8 participants last post by  FordService 
#1 ·
I saw a thread for this from 2011 but they didn't seem to know what exactly was causing it. When im sitting at a light with my foot on the break, occasionally there is a noticeable vibration. You can feel this from both the drivers and passenger side. It isn't too extreme but it was enough for two people to ask me what it is. Does anyone else experience this? My car has about 2200 miles on it. Thanks!!
 
#5 ·
It wouldn't be that the mount was bad that some of the people want to change at least one of them, but that's the rear motor mount (RMM) or power train roll restrictor. That one allows the engine to tilt under load and absorb some of the slack in the power train, but too much slack leads to a disconnected driving experience. The stock mount is mostly made of rubber there where as the Mazda MazdaSpeed 3 rear mount is much more solid. Although that might nominally increase engine vibration felt in the cabin, it can help tighten up the roll of the power train allowing for less power to be wasted in this fashion. But its not likely to show up on a dynomometer.
 
#6 ·
This was one of the first things I noticed when I picked up my "new" used Focus a couple of weeks ago (I never noticed it on the test drive though). I would be sitting at the lights with my foot on the brake and the car would be vibrating during idle.

I took my car in to a Ford dealership this past Wednesday and told them about it and they fixed it. The previous owner of the car would have received (so I'm told) notification for 2 recalls, one being the sync and the second being reprogramming the PCM, TCM and ABS module. This second recall is what fixed the shaking car during idle and it in fact did fix mine, recall 12B37B for your reference. It may fix your issue, it may not but it's worth a shot.

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#8 ·
12B37 focused more on the traction control/abs/ powertrain and transmission control modules and strategies. It however did not fix the vibration at idle as it can and will fade in and out of the cabin depending on fuel quality, or just the general mood of the engine it seems. Direct injected engines are also running at higher compression closer to that of a diesel and this might magnify the four cylinder shake at idle. Sometimes its smooth, other times less so. Although my car was built in a date range beyond the effect of 12B37.
 
#10 ·
Well I bought my Focus from a Honda dealership (I know it makes no sense) and made an appointment with the closest Ford dealership to my work. They took it in with no questions asked and ran the recalls. I did explain to them I wasn't the original owner and wouldn't have received notification of the recalls and they were fine with that as the car is still under warranty and transferrable.

suss6052, I can't begin to understand the exact mechanics of an engine and its behaviour but it did seem to help. I will make sure to keep close attention to the scenerios you described to see if I will experience the shaking again.
 
#13 ·
With the A/C on mine idles very smooth. Turn off the A/C, the RPMs drop a little and I get a vibration. Not bad but noticeably different. It doesn't seem the be a problem but it is a little annoying. The next time I am at the dealer I thought I might ask if the idle could be adjusted.
 
#14 ·
I haven't noticed a difference in idle between a/c on and a/c off at idle with a foot on the brake, but idling in park with the foot off the brake seems to be about 680 rpm target idle with the DCT at least vs the 750 with the foot on the brake with or without the a/c on.
 
#15 ·
I was thinking maybe it had something to do with the whole "switching to neutral" thing when your on the break but I never really completely understood how that worked. Im talking about like when you sitting on an incline and slowly let off the break; it will roll back a little until you fully let off the break
 
#17 ·
With the DCT the car has to be in neutral at idle or else it would stall. The same as letting out the clutch on a manual transmission car at zero vehicle speed. If you had a torque converter the engine is separated from the wheels via the torque converter and allowing for the slippage cooled by fluid trapped inside the gearbox. Since the mechanism on the DCT is mechanically similar to a manual gearbox.
 
#20 ·
If your car feels mostly smooth then random harder jerks at idle, you should reset the car computer by disconnecting the battery for ~30 minutes or something and letting the engine idle for 5 minutes when you start it back up.

If your idle is smooth but causes a lot of vibration in general, then it's the motor mounts.

12B37 increases idle RPM from 700 to 800.
 
#21 ·
My car was built after the date range for the 12b37 update, but still idles at approximately 680 rpm with the a/c off and in park with my foot off the brake, or 750 rpm foot on the brake in gear with or without the a/c on approximately. At no point is the idle over 800 rpm per the digital tachometer displayed in test mode. Once you take your foot off the brake the rpms increase as the car begins to engage the clutch for 1st gear.
 
#22 ·
...When im sitting at a light with my foot on the break, occasionally there is a noticeable vibration. You can feel this from both the drivers and passenger side...
Hi Michaelc1220,

I would recommend that you make an appointment at your dealership. Ford certified techs are in the best position to diagnose and repair your vehicle, in addition to giving you some peace of mind. [:)]

I'm happy to escalate your case to your region's Customer Service Manager; just send me a PM with your VIN, dealer, mileage, and daytime contact number. I'll get things rolling!

I think it has to do with the direct injection.
I've seen some posts fly by about bad motor mounts. That could cause vibes at idle.
This was one of the first things I noticed when I picked up my "new" used Focus a couple of weeks ago (I never noticed it on the test drive though). I would be sitting at the lights with my foot on the brake and the car would be vibrating during idle.

I took my car in to a Ford dealership this past Wednesday and told them about it and they fixed it. The previous owner of the car would have received (so I'm told) notification for 2 recalls, one being the sync and the second being reprogramming the PCM, TCM and ABS module. This second recall is what fixed the shaking car during idle and it in fact did fix mine, recall 12B37B for your reference...
If your car feels mostly smooth then random harder jerks at idle, you should reset the car computer by disconnecting the battery for ~30 minutes or something and letting the engine idle for 5 minutes when you start it back up.

If your idle is smooth but causes a lot of vibration in general, then it's the motor mounts...
Thanks, everyone, for bringing good information to the table. I'm sure Michaelc1220 appreciates it!

Crystal [thumb]
 
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