Mustang Evolution Forum banner

Engine vibration when stopped in gear.

39K views 16 replies 10 participants last post by  Hunterhutton 
#1 ·
When I'm in drive but stopped, say at a red light, my engine and car vibrates pretty violently. If i switch it to neutral or park, it stops instantly. I'm thinking it may be the transmission mount but I don't want to buy a new one if that's not the problem. Has anyone had a similar issue with their pony??

I have an automatic transmission by the way.
 
#7 ·
So I removed the transmission mount and inspected it. Everything seemed fine. I rotated the insulator which sits on the crossmember, and replaced the crossmember. I also removed all of the sparkplugs, inspected, re-gapped, replaced one bad one, and reinstalled the rest.
I had replaced the fuel filter a couple of years ago.

In the end, the vibration remains. I doubt its the motor mounts because the vibration completely stops as soon as I accelerate, or when in neutral. I've also revved the engine while in drive with my foot on the brake. The engine torques to the right, but doesn't jump as i would with bad motor mounts.
 
#8 ·
So I have noticed that the vibration only occurs when the AC is turned on. If I rev the engine as slight as possible, the vibration stops, but returns as soon as the RPMs return to "idle". Is the engine supposed to increase RPMs when the AC is turned on to compensate for the extra load? If so, could this be an electrical issue where the ECU is not recognizing that the AC is running, or not sending a signal to increase RPMs?

Alternatively, I can change the RPM idle limit with my tuner. I may give that a shot to see if it helps.
 
#9 ·
2007 GT/CS

I have a very similar problem with my car, I have a 07 GT/CS automatic, my car will do the same thing rattle and vibrate while at a stop sign but as soon as I put it into neutral vibration goes away. I have changed the spark plugs, they needed them and I still have the vibration. Do you still have that issue?? If so what more have you do or checked??
 
#11 ·
I have also read bad motor mounts will cause this. Happening on my 07 Focus. Thinking about replacing mine.


Sent from my iPhone using Mustang Evolution
 
#13 ·
Is it idling at significantly lower rpm than it used to? There is something in the electronics called an idle sensor, and some cars do indeed link it to the AC so that the engine does not lug at idle when the AC kicks on.
If it is only vibrating when the AC kicks on, then it could be anything from your idle circuits to the AC clutch.......
 
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top