Upon starting (or attempting to start) my 1999 A4 1.8L 4cyl turbo, it dies upon turning over, and only when given the gas, will it give me RPMs, and dies or has 10-20% idle RPMs when idling. Any ideas what this is (CEL is on too).

In higher RPMs, engine clicks, and exhaust is not smooth...everything just seems rough and not getting enough fuel to idle, etc.

Not sure if this is related to previous issue, but I also recently had a drain on the battery, causing the car not to start after a few days. I had battery replaced, and they checked for the draining source, but the car still drains when not started for a week or so, and everything is dead.. (Any suggestions there, too? had it looked at and they couldn't find the drain source).

Thanks!!