Need Help.
Back in October we got in the car to start it, it would fire but only run momentarily then die. Tried this several time and noticed that CCU light was on. The car just broke 50,000 miles and just went out of warrant. We had it toed to a VW dealer in Bloomington, In. The said there was a problem with the CCU. They reprogrammed the key and got us going for $76bucks. She took the car in for for service, and the reprogramed the other key and sent her on her way. Not two miles down the road the CEL come on and she went back. I'm not sure what the code was but it has something to due with the number 1 cylinder, they didn't know what to do so they reset it and sent her packing. She's noticed the gas milage has slipped about 40 miles per tank and shes noticed that when starting the car (especially when cold) it stumbles and shahls but not consistently. So this morning the CEl come back on and i took it to Advance so they could scan the codes. They retrieved the following codes. DTC (codes) P2181 Engine cooling System Performance and DTC Pending (codes) P0118 Engine Coolant Temp Circuit High Input. Where do i start? Where on the block or intake is t Coolant Temp Sensor Located? I did check the antifreeze and it is at the proper level and the car is running the same temp it always has. Unfortunately the car is out of warranty and they don't want to fix it even thought the extended warranty just expired. I can fix this with a little direction.

Thanks,
John