I am guessing "A" looks like mix screw. As many dealers up there in CA should be able to find someone that knows. If not try Daihatsu America Tech. Assistance 800-777-7070, or better yet "Daihatsu Help"
(Leon)626-333-7897 Tech. Assistance. Leon has some pretty laid back hrs. but he knows these little trucks. You can get a service book from Lulu Publication.