Strange idling problem with my Grand Am

Hey All,

Hope you can give me a hand here, I'm trying to avoid taking my car to the shop if I can help it. A couple of days ago, I noticed this strange rocking when I'm idling at a stoplight. It only happens when I'm in drive, but I think I can hear the same pattern when I put the car in neutral and listen to the engine.

Also, in conjunction, I noticed that when I lightly press on the gas after the light changes to green, on occasion, the car feels like its going to stall, then kind of lurches forward. Once, it felt like it went backwards a couple of feet before proceeding.

I did notice though, if I push down rather firmly, you don't notice anything is wrong. Except for that irritating rocking.

Any ideas?

Thanks in advance.
-Jeff

I would bet its a vaccum leak and its causing one of your sensors to go wacky.. check over them..

this can be a number of things. this is what I would do.
1. open hood, start the car, hold down brake at all time during this test, keeping a eye on the engine put it in drive give it a little gas. (looking for engine movement up or down) do the same for the reverse gear. If engine is moving up or down replace motor mount and trans. mount.
2. How long has it been since you replace the fuel filter? remember this part is cheap in most cases.
3. Check your pcv value (located on the valve cover replace it if its dirty) and hoses. It amaze me to see people bring ther car to the shop for idle problem i the hoses were claps or the pcv. (pinch all hoses feel and look to see if they too soft do this with the engine at normal temp)