Gents; Working on my boy's 2005 Classic with the ecotec 2.2 engine with 140K miles. Changed the plugs oil and filter and did a transmission flush. Been an awesomely dependable auto for several years. The car is smooth and quiet but there's one annoying issue and that is a rough idle. Anything other than idle the engine is velvet smooth. It sounds like an egg beater at idle but wont stall nor hesitate on acceleration. I can feel the vibration when I put my hand on the valve cover at idle. The motor mounts seem ok...can't rock the engine....but with a vibrating engine not sure new mounts would smooth things out anyway. I don't want to throw parts at the car so I'm hoping one of u gents can lead me in the right direction. Hope all is well with all of you and thanks for any help.