yeah, after an accident I now live a life of constant pain, and apart from regular surgery on my chest, I take codeine regular. Which doesn't seem to give effects, but if I don't take them for a week, then start again, I am only good for dribbling in the corner! It's scary what damage kids could do without realizing!
Back onto the zed in question, sounds silly but can you 'follow' the scent to a point in the car, or do you just get an overall smell lingering? wouldnt that say if its some weed in the car, or just the aftermath of a druggy using the car?