Hello All,

The engine bay area of my 2007 Mustang V6 automatic with 167,000 plus miles shakes very often when I come to a complete stop at a stop sign or a red light or even at a fast food drive through especially if the front of the car is at a downward incline. If I put the car in neutral and still keep my foot on the brake, the vibration stops, but if I put it back in drive with my foot still on the break, the vibration returns.

I do not feel the vibration while the car is in motion or when I hit the break pedal and the car starts to slow down.

Within the last two years I have replaced the catalytic converters, cooling fan, shocks and struts and tires. The mechanic who installed my struts made sure that the sway bar links were attached properly, so it can’t be those that are causing the issue.

I’ve read online from various posts with a similar issue that it could be any number of things ranging from bad engine mounts, bad transmission mounts to bad spark plugs.

I literally have no idea what it could be.

Any ideas?

 

You can check the engine mounts by looking at them while someone
goes in and out of gear. Usually it's the Trans mount.

 

Maybe the torque converter in not unlocking

 

If so, It would stall once you came to a stop. That's why lockup is generally not available in
1st gear.

TCC lockup allows a 1:1 ratio, crank with TC, there is no slip inside the TC. It would be
almost LIKE coming to a stop with your manual in 1st gear, and you not pushing the clutch
pedal; the car would stall.

You'd also be getting a CEL with P0740 or P0743 code.

P0740:
The transmission not shifting in or out of a particular gear
The transmission may shift harshly
The torque converter clutch may not engage or disengage causing the vehicle not to move
The engine may stall
The transmission could overheat

P0743:
Stalling when coming to a stop after cruising speeds
Shudder on take off
Shudder when coming to a stop

Both are TCC lockup circuit failures, or mechanical failures.

A TCC locked up at idle will stall the motor.

 

I'd have to agree with 08'MustangDude. I have had no error codes and my engine has NOT stalled.

 

For what it's worth, I ran into this exact same problem with my '08 4.0. Gets worse with the A/C on, I'll bet.

I spent a lot of time and money replacing parts...runs like new now...but the vibration was still there.

Anyway, the way I finally resolved it was with an SCT X3 tuner. Bumped the idle to 725 RPM Drive, 675 RPM Neutral. Presto, no more vibration.

I'm not suggesting you do that, because on an enthusiast site, you'll always get purists telling you that's not the way to fix a vibration problem. So feel free to spend a ton of time and money replacing parts instead!

 

CtCarl, did you replace the transmission mount and engine mounts?

 

I'd start there ^^^

Been there, done that, on other vehicles where I didn't trust my instinct about vibration issues at idle. Chased all sort of other things (fuel, spark, etc). that looking back, had no foundation to be considered.

Start at the mounts. Sometimes it really is the simple things.

 

Sure did, even though they looked fine and there were no other symptoms. Be nice to have that $500 back.

 

Mine growls at idle, and in 5th gear w/ TCC lockup at 2000 RPM...
I will probably need a transmission soon...