Jay1, The reason I asked what you were stripping was to see if it was a rusty car from the twenties, or something newer. If it's a pearl job, then the paint couldn't be older than the sixties.

I wouldn't worry about leaving some well-sanded paint, as long as you use a catalyzed primer over it.

Just remember that if you see any signs of peeling, blistering, or cracking, take it all off in those areas, or it may cause the new paint to fail.