Did you ever replace your K40 relay or the MAF? If there are no fuel leaks (check under the black plastic cover too), I'd suspect those two. But if there are any pinging noises while the engine is missing, it's probably the injectors.

__________________
2004 VW Jetta TDI (manual)

Past MB's: '96 E300D, '83 240D, '82 300D, '87 300D, '87 420SEL