Originally Posted by foosh
I drove a 2007 RS4 for 15K miles, and I only used Shell (Top Tier), unless I had no other choice. I only experienced the misfire once, which did set a code. A simple dealer reset did the trick. However, I am aware that it is a problem on direct injection engines.
Shell claims their latest "nitrogen-enriched" fuel is an attempt to try to deal with the problem. I have no idea whether their marketing claims have been verified by impartial technical analysis, but they claim the "nitrogen-enrichment" process makes the additive (cleaning) package more stable at the higher operating temps seen in such engines, thus making cleaning more reliable.
Only time will tell . . .
I have heard similar comments about Texaco's Techron additive. There is no doubt that the fuel technology is playing catch-up at the moment but I don't think it will be much of a problem long term.