I think mjp was saying that if Bukowski hadn't been so ill and really knowing what his prognosis was, then he wouldn't have written Pulp when he did. I think it can only ever be interpreted as not only a last novel but really as a conclusion to a career and perhaps a message from Bukowski to many who knew him - either personally or through his writing. Maybe even a personal critique-cum-epitaph-cum-eulogy. If that's possible...
I certainly think its an odd book. I started my Bukowski habit with a novel - Factotum - and read all I could afterwards, enjoying both fiction and poetry. But I was surprised and perhaps confused by Pulp, the way its written - the pastiche, the themes and the characters. I know I was disappointed by the ending. It sort of fizzled out (like life?). I've read it several times over the years, and while I can't say as mjp did, I don't care for it, it's definitely far from a favourite. I'm sure I'll read it again, as in some ways its tells part of the whole story - like Charlie says, Bukowski's writing is at least partly autobiographical - even if, as we speculate elsewhere - many of these autobiographical tales are more myth than fact. He may not be called Chinaski, but there's still some Buk in Belane.
I'm not sure whether Bukowski achieved what he set out to do - who could know that? And its easy to read lots of things into it about how Bukowski felt about his life, impending death and his image and career.
BTW : I have to say that although I also think that Bukowski's writing is partly autobiographical, I would still say his other novels can be seen as Fiction. And outside of those he wrote so many great (and often off-the-wall) short stories, I couldn't agree that he was "on his way to fiction". He'd always been able to create great fiction, even if he drew heavily on his own mad experiences and those of other people he'd encountered.