So the charcoal canister vent valve seems to be the culprit. I dropped my car off to have them install the one I ordered and they informed me the one I gave them wasn't the same and sent me side by side pics, and they were correct. So I had a used canister and valve that i ordered, but the Y shaped hose nipple on it was broken off and rendered the canister useless. So i brought it to them so they could use the valve. they installed it and the car would barely start, and would nearly immediately shut off. They put the old one back on and it ran again.
I have looked and not been able to locate a correct valve. The one I ordered was for a 2004 SLK 320, and it does show a pic of the part that arrived, which is clearly different from the crossfire one which does not appear on rockauto nor anywhere I looked.
Has anyone found one anywhere?