As of September 27, 2018 there should be no worries about getting ULSD (Ultra Low Sulfur Diesel) anywhere in Mexico. OK, i should qualify that - except out in the boondocks where the "gas station" is a front porch with a 55 gallon drum.
Pemex officially declared all their refineries have been upgraded to deliver ULSD. So, all you Deadheads and 60's folks will have to go somewhere else for your LSD.
Thanks to Ted White for this info.