Ok, this is driving me nuts and any help would be appreciated.

Symptoms include:
Significant vibration through the cabin when the car is in park and in neutral.
Vibration increases when I shift to drive and stay stationary.
Vibration stops completely when I shift to reverse.
When driving slow uphill the vibration seems worse and right behind the firewall.
Car starts with a real rough jolt when I am parking on an uphill and starts perfect when parking on a downhill.

Recent Work:

Replaced rear engine mount with non OEM.
Replaced side engine mount with OEM.
Replaced transmission mount with OEM.
Removed and tested front mount and vacuum. No problems there and tried car with a new front mount and vibration did not go away. Put old mount back on.

Any suggestions on what it could be would be greatly appreciated!!!!

 

Are you driving a 99TL?
If so, is the rear a vacuum mount?

My rear mount is shot and I get a lot of vibration when in park and more when in drive but foot on brake.

 

Thanks
Dammit. I thought that came up on my post. Yes, I have a 99TL.
Mine does the same. My next step is to get the rear mount replaced with an OEM. From what I can tell from the diagram, it looks like the rear mount has a line running into it so I assume it is vacuum / hydraulic?

 

 

Thanks NSXNEXT

I was just looking at the same diagram. The vacuum to the rear mount was possibly the only thing that hasn't been checked. I am going to take it back to the garage that has been doing the diagnostics (AAMCO on Arbutus in Vancouver, BC. Fantastic service. I cannot begin to say how great the customer service is there) and see if that is the issue.

 

dummies left the vac line off when the aftermarket mount didnt have one??

 

Gotta assume they didn't plug it either.
If I were you, I would try plugging the end before you go spend the money on a new rear mount. See if that reduces the vibration.

 

So I took it back for another look and the line appears to be connected to the rear mount.
They didn't check the vacuum though. So its either a crappy / defective rear mount or, crappy vacuum seal or something completely different. I take it to the garage that did the work on Monday to put in the OEM part. They're only going to charge me the diff in $$ between the non OEM and OEM part.

Any other ideas?

 

did the problem start only after you had the mounts replaced?

 

I believe so. Hey, what is part #34 in the diagram?

 

That's the mount for the years that do have the hydraulic connection. 02 and 03 I think?

You don't want that one.

 

Right

My front and rear are hydraulic. The side is just rubber.

 

Correct.

As I mentioned, I'm having similar issues and I know my rear (and possibly front) mounts are shot. New mounts are hopefully going in soon.

 

I picked up my car yesterday after having the non OEM rear mount replaced with an OEM. The mechanic said the vibration was still there and had no suggestions as to what it was other than maybe the transmission. Both he and the owner had little else to offer. I get in the car, start it up and the vibration is gone!!! I drove it around town a bit and still gone. I started it on an uphill and downhill, gone, gone, gone! Not only is the cabin vibration gone, but the AC used to rattle like crazy when it was turned on and that is gone! I’m not sure if it is the difference between the two mounts, or they missed something installing the first one, but it runs as smooth now as when I bought it. Lets hope it lasts.