Photoshop :: How To Avoid Wand Selecting Both Sides Of Erased Border

I have eraser tool trimmed all round an item I wish to take out to another photo, so lets say I have a car, round its edge is now  an 8 pixel border of transparency, car within, road scene outside, I click the car and get parts of the picture both sides of the erased border ,  I just want all of the car, or alternatively I click outside the erased border and get bits of the road scene but also bits of the car.
 
I have tried contiguous on and off, select all layers on and off, different wand tolerances, various combinations,...have I overlooked one that I can wand the road scene and it will select all of it up to the gap around the car ?  I can then expand selection a couple of pixels and delete out the road scene.
 
So far I am left with carefully picking my way around the middle of the border with the straight line selection tool and erasing chunks away that way. Having taken ages to go round the edge of a complex shape , to have no option but to repeat the path with the stright line tool is a pain. I use a variety of brush sizes/settings and quickmask mode to initially select out the item. I should have used the lassoo tool then inverted selection, it doesnt allow for a variety of hardness in one selection and you cant sew what exactly you have got, unlike a pink edge.
 
Its simple stuff like this that I hope Pshop after many years would have a tool for, as well as all the luxuries/gimmicks.