Hate to say it..but my ESi did this as well a week before I spun a rod bearing. Had practically the same symptoms-had to keep my foot on the gas on start-up or it would die, but would be fine after the car warmed up and ran for a bit. I dreaded having to stop at lights and signs for fear it would die. I just assumed it was a fuel issue at the time and scheduled it for service..shop told me that they could fit the appointment in the week after, and like I said, it never made it. Bearing entirely went and car sounded like a tin can in a blender. Anyway, have you checked your oil at all for shavings?