Heavy vibration while at idle in D, not when in Neutral... 08 TL-S
 

Yesterday on my 08 TL-S I had a valve adjustment done, new plugs, outlaw eng. spacer kit, replaced all 3 trans press. sensors, and replaced a broken upper trans mount. The car runs alot smoother now and the engine is certainly more quiet.

We first started the car and the sensor on top of the TB wasnt fully plugged in and the car got a nice surgy idle... put it back on all was well for the exception of a CEL.

Unhooked the battery this morning and did a TB "relearn" procedure I found on this site (if there even is one, idk I tried it anyway for the hell of it) and the CEL went away.

Now when I am stopped while in D I get a heavy vibration similar to having very stiff engine mounts, it actually makes the dash rattle and goes away completely when I shift the car into Neutral... I turned the A/C on and it got even worse when in D with the car stopped.

Any idea's as to what is causing this? I thought maybe idle speed but it seems to be exactly the same as it was prior to the work yesterday... and I do not recall the vibration when I left the shop and drove home.

Any help is appreciated :thumbsup:

127 views and not even a suggestion?

Front motor mount?
Something else?
A monster?

I'd say motor mount. But,was this problem there before you did all these Mods? Also, are your RPMs surging or do they coincide with the vibration?

:rofl: looks like you know what you're doing any way.
its kinda hard to diagnose a vibration from the interwebz.

check your mounts and if they are broken then a monster caused it

Its probably the engine mounts. Either that or since you did some work targeting that problem, you probably pay more attention to things and notice the vibrations more. Another possibility would be the Outlaw spacer causing a vacuum leak if not installed properly.

No vibration prior to mods at this particular rpm not moving, I had the clunk when shifting from park to reverse and vice versa, and a good vibration in 2nd gear under load. The upper mount was clearly broken just from looking in between the battery and airbox. No RPM surge and the rpm appears normal, car runs great.

I know how to work on cars, but I have only had this car 30days now and completely new to TL's, I am not coming up with much through searching, seems mine is a little different then most. Only thing I found through searching was possibly the front mount... how can I tell its broken or not it seems like a completely different "monster" from the basic upper trans mount.

Passenger side upper mount "appears" fine, how the hell can I check the rear? lol

Have you heard of anyone breaking the lower trans mount?

When the car is shifted into N sitting at a light it idles like it use to, butter smooth. There is no way on earth I didnt notice this before lol its rather intense, I compare it to my Integra with solid mounts and solid torque mounts, just not as intense... like I said it makes the dash rattle.

i have a 2005 tl and im having similar problems. i can feel bumps(erratic) when it idles, that i think came on after i replaced the oem filter with a K&N filter. I am averaging 21/31 city/hwy mpg. I get a vibration during early acceleration continuing sometimes up to 40mph and sometimes it dont happen at all under the same conditions(weather,route,load,gas etc). i changed one engine mount and it didnt fix the problem so now im looking to change the rims or better yet...rotate the rims and see if the problem continues. I dont see anything loose in the suspension but i will keep on looking.

For your situation...maybe a faulty MAF sensor. something isnt retarding the engine while the the vehicle is at idle and all that pwr is transferred and dissipitated at the engine mounts thus causing a vibration. Also faulty coil packs or spark plugs. at higher speeds momentum cancels out faults in a plug/coil and you wont feel it until u are at low rpms. I once changed my plugs and forgot to connect the clips to 2of the coil packs(i was in a rush). i started the car but instantly felt a choking idle. i drove to a nearby parking lot and i noticed that the faster i go the smoother the idle became (anything over approx 25mph i wouldnt feel sh*t, but at lower speeds/rpm it was choking). i got out reexamined and realized that a couple of the clips werent connected. i reconnected them and all was resolved.

If this is your issue, the front mount has a thin, rubber cover. Shine light on it, and you can reach down and try to lift that membrane cover, look and feel for fluid and breaks at the top of the rubber mount.

You can also test the front mount for breakage by observing it under light load: Get a helper. Have them put the emergency brake on, press the brake, put car in drive, then (lighly!) tap the accelerator for a moment. You observe the engine--if it tips up more than about a half inch, then (at least) the front mount is broken. :whyme:

Here's the front mount DIY that might be helpful. https://acurazine.com/forums/3g-tl-problems-fixes-114/diy-front-motor-mount-854098/

Good luck!