My car coded P1078 soon after getting an oil change. I reset the computer but the SES with same code occurred again less than 100 miles later. It appears to be running just fine except for a few occasions of high idle as many others have noted. Now one cause that is often mentioned but I haven't noticed discussed is debris interfering at the sensor location. I thought since I had just had an oil change that this could be a possibility for my situation and there may be a solution other than replacing the sensor. Is the sensor itself able to be unobstructed of this debris, if that's the cause?

 

Well, it seems to have cured itself over a month after it started. Still would be interested to know if there's an answer to the question. Thanks.

 

I was wondering if you ever figured anything out about it. My car is doing the same thing(P1078). I replace the sensor and still throws the code (2 different sensors a cheap ebay one then a oem one). When it is just warming up it idles fine (600rpms) then about 30-40 mins of driving it will start to idle about 1100 rpms. I have just given up on it as it has no effect on the cars driving, but I hate seeing the SES light on the dash.

I got the code about 100 miles after changing my oil with mobil1 5w-30 full synthetic

 

Were you able to resolve the issue? I'm having the same issue...