idle rpms too low, excessive vibration

[Gadget01]

Quite often when the engine is idling with the foot off the pedal, rpms get so low as to cause my inner door panels to vibrate excessively. I'm not talking about the interior panels, but the door frame that the window motor is mounted to. You can typically only hear the vibration because the panel covers it, but I have had my panels removed quite a bit lately from doing custom speaker and dampening sheet application, so watching them flex like a giant subwoofer with about a half inch excursion is sort of unsettling.

I noticed if I give it just a wee bit of throttle and get the rpm's up by a couple hundred, it goes completely smooth again and vibrations disappear. Engine idle speed is a basic function and I assume the computer controls it. Is there any easy-ish way to adjust it a notch higher? Maybe just a simple mechanical adjustment on the throttle assembly?

I have a very new rear motor mount, as of the day I bought it last year in April. I'm wondering if I should go ahead replace the other 2 anyways, even if they don't play a part in this but I'm guessing they probably do.

[Bugone]

I had this a while ago, felt like idle was dropping out a bit. I replaced the spark plugs and its all fine now. Might be worth a look if they havent been done. It might even be one of them needs tightening, as I noticed two of mine had come a bit loose.

[Gadget01]

I didn't get much a maintenance history when I got the car, so I have no idea if they have ever been replaced so it might be a safe assumption they are originals. Mileage is at 173k.

Front engine mounts, a set of plugs/wires, fuel filter, air filter, and maybe a new set of dzus fasteners for the fender skirts since mine just fall out when they are supposed to be captive.

I just need to determine which index model the plugs they are... A/B, correct?

[Willie Williford]

What are you showing as the idle rpm?
The IMA it'self should energize and take out most of the vibration at idle.
Like Bugone said, plugs would help.

The majority of plugs here in the US are B.
Check the stamping on the head or the plug itself.

HTH
Willie

[AbCaRed00]

?perhaps the Idle Speed controller?; there is a idle speed adjustment in the throttle too and procedure in repair book is noted as well.[link to thread]