Whilst technically still for sale, she is never unloved... just unlooked after 
I guess I advertised her at the wrong time, just before the snow and ice struck, then it was crimbo, so no takers. So the song remains the same, although who knows what will happen if the spring comes early and the sun gets on her back once more. Who knows, maybe something wonderful will happen and she'll return to her beloved Sarthe once more. Or maybe a troupe of travelling unicyclists will buy her for a tour of Uzbekistan?
Or maybe the wrecker's torch awaits...
So, reading between the lines:
"Whilst technically for sale" = In your heart (if you have one) you don't really want to sell her
"If spring comes early and the sun gets on her back once more" = your heart (if you have one) will pump guilt to your brain when you see old Sol's rays glinting off her tarnished chrome; the sun is out today, so I bet that process has started if you can bear to cast a glance in her direction.
"maybe something wonderful will happen" = you will get off your ar*e and do the requisite work needed to return her to the road
"or the wrecker's torch awaits" = when your whisky intake overcomes any last vestige of guilt at being so horrid.

MG Mark