Vibration at idle

[Tampa 735il]

Since I owned this car at idle I feel a vibration. Idle is steady bring up the motor to 1,000 or so it goes away.
I replaced the motor mounts it seems like the drive train is passing it to the body.
The idle air controler has been cleaned and car runs great but can't seem to get the idle issue addressed; anyone had or has this issue?

[lincolnmaster80]

What RPM does it idle at?

[lincolnmaster80]

I would check to make sure that the ignition coil isn't goosed. It maybe functioning just enough when at idle but the ignition system springs to life because alternator is producing a bit higher output. Check all plug wires are clicked in all the way on to the plug and into the distributor cap. The distributor cap and rotor aren't corroded/in need of replacement. Could be a spark plug is no good.

735 is different than a 750, but when I had discovered that one plug wasn't firing as it should, my idle smoothed out considerably. You'd be surprised how well these things can run with one cylinder down.

If it was drivetrain vibration, I would think the problem would manifest itself when moving. I'll do some digging.

Do you have the fly-by-wire throttle or the cable style?

[Tampa 735il]

I have had this issue since I purchesed this car back in 05 and put it away for 5-Years.
Everything is new, Plugs, wires, cap, rotor, valves adjusted, vacuum lines and leaks accounted for.
It idles rock steady at 650 or so, this is a vibration issue not an unsteady idle. New motor mounts this week I am going to place a jack under the tranny and see if this changes anything. I also understand that an alternator mounting bushing may go bad and am starting wondering about my cats being plugged.

[lincolnmaster80]

Ah okay, I understand. I linked vibration and idle together. But you will be surprised how stead and smooth these cars can idle IF any of the ignition components were naffed. Anyways, I think you're on the right track with the tranny/tranny mounts then, you probably didn't need me to tell you.

There was one thread I was reading through and the owner who seemed to have a similar issue asked if a bad torque converter could cause this. There was no responce but I got to thinking that it might be possible if the clutch packs (or whatever the system is called inside a T.C.) are perhaps not...erm...idling properly??? Does that make sense? Or maybe a bearing has worn and the torque converter is wriggling enough to cause a vibration. Just throwing a few ideas for you to mull over. I've personally haven't really heard of this issue before as generally it's usually related to idle.

[lincolnmaster80]

Also just saw your other post about tranny mounts...