Hopefully this is something simple like a failing hose or something...but here goes:

About a month or so ago I got a SES light with code PO128 (engine wasn't reaching proper operating temps). AutoZone said it could be a bad thermostat, low coolant, and a number of relatively cheap things. So I check my coolant level, and the coolant in the overflow was low. So I buy some coolant and before I even get home to put it in, the SES light goes off on it'* own. Upon researching PO128, I found that if the vehicle completes 3 successful driving cycles without throwing the PO128 code, the SES light goes out. Apparently thats what happened in this case.

So last week, I was driving about an hour away, and the SES light comes on again en route. PO128 was the culprit once again. I drive with it on for another day, and the light goes off again. So I start thinking well...if it'* not getting up to operating temps, maybe I should let it warm up before driving it...it is cold as hell right now.

Well...yesterday I noticed leaking coolant in the driveway, and smelled it as well. It was NOT leaking until the past couple of days...atleast no at the volume that it is now. It is literally POURING out of the left side of the engine compartment, I can't really tell where though. But it is a nice dripping stream. Seems to only be happening while the car is running though, and stops shortly after I turn it off. Any ideas? I currently don't have an SES light, but I'm sure its a matter of time.

Check the bottom and upper coolant elbows, that'* my guess.

By the "left side of the engine", you're referring to the driver'* side, correct? If so, check for leaks at the throttle body.

Nope, it would be the PASSENGER side. I meant left as if you were looking @ it w/ the hood open.

It'* a significant amount of leakage...so much so that it trails up the driveway when I pull in. It seems to be directly below the overflow tank...perhaps the tank has a crack in it - but would that explain the random PO128?

OK. Sides of the car are referenced from as if you were sitting the driver'* seat...so, left is driver'* side, right is passenger side.

If your coolant level falls low enough to cause it to below the coolant temperature sensor, it could think that it is not warming up quickly enough. Pull the tank and check it, and also check the elbows as Petraman suggested.

It could be your water pump.

Fill up the coolant and try to see where it is coming from.