My 05 V8 Limited has a lumpy idle. I have had it to the dealership and they acknowledge that the idle is not smooth but they tell me there is nothing to worry about. I have tried all different types of gas with no luck. It seems worse when the AC Pump is running. I'm going to ask to drive another 05 V8 when I am at the dealership next and if the idle is smooth, I will be pushing to have something done.
I didn't buy a Toyota V8 for it to be rough at idle.
They don't seem to think there is a problem, but I once had a V6 Accord that had a slight shudder while going into overdrive and the dealership told me that it was slight and not to worry about it. I left it alone until one day the car stalled at a stop light when I stopped and that was it for the Torque Convertor.
I really wish I knew someone in the Ottawa area in Canada with an 05 V8 I could sit in for a minute to see what their idle is like.
I hate problems like this. I wish the thing would blow a code and it would be all done with.