i am still guessing that the PM was imaginary, but there are so many 'nicknames'
for everything that exists down in Louisiana.

I believe that I have one PM lyric mystery figured out:
pumped a lot of tane down in NO,

well, everybody knows that NO is a huge oil and gas production center for the US,
the product of these refineries get 'pumped' north.
the products that get pumped are the various petroleum products..
you know,,,ocTANT, buTANE, meThANE, --and all the other hydrocarbon chains
(i was a construction electrician working in the Louisiana oil industry, and
(i was NOT a pumper, -a pumper was anybody that simply operated the
refinery valves and pumps, not much more educated than a dishwasher)