My TD, an 89 Jetta I stuck in my Caddy won't start at the most inopportune times. Fuses OK, Glow plugs are new, relay has been replaced, fuel is OK but will not start at times. I go for a few days and all works fine. Than when I least expect it, it will not start. I hope somebody has a suggestion as to where to look. So far nothing looks unusual. Peter