One of theories behind the injector failures is that when and HPFP went bad, oil from the HPFP made it in to the injectors and clogged them. How much truth is there to that.
As somebody that has experienced a leaky injector and had couple bad injectors, this is not something I would consider, especially because I haven't really seen any talk of it or data to suggest that seals are drying out and failing.
I don't think the lower percentages of ethanol most are seeing at the pump would merit anything of this nature. I also read quite a bit from people that are running as high a percentage as I am and much higher...haven't read of anybody adding oil to their fuel
Is there some merit to it...maybe, but I'd have to see a lot of data on it before considering anything of this nature...JMO