Hello. I have had a problem with a 2010 4D with the engine pinging on a grade. I used Sunoco plus and it really did not help, however the premium did. Went to the dealeships, and only one decided to test drive the vehicle, and replace the PCM module even though there were no fault codes. I used regular, and it helped a little, but then I used plus, and there was a world of difference. Hope this helps others with the same problem.