Hello...I've got a related issue -

I turned my car on one morning and within a minute of normal driving the check engine light went on - then I noticed the coolant temp steadily rising whilst I was driving gently. anyway before it hit the red line (and after waiting an hr) I took it to a shop and they pulled a code P0116. The check engine light went out just prior to getting to the mechanics. Anyway - I re-plated (out of state) the vehicle the day prior to this happening and I have to get the car inspected within the next few days - the car has run fine after driving 20 miles with no overheating (never had an issue before) - The mechanic couldn't diagnose the problem after looking at the car and running it for 1/2 an hr a day after I dropped it off.....

2 questions:
1) what's the most likely cause of the temperamental overheating? Temp sensor /dodgy water pump?

2)How do I get the code to drop off - so it passes state inspection - do I really need to drive ~ 100 miles?

Cheers,