2000 Jetta won't start


#1

I own a 2000 Jetta TDI 5 speed. Last week I had trouble starting it. If I could get it started in the morning and just ran errands, stopping and starting was fine. But the next morning it would take 5 minutes to start it. I took it to a referred import mechanic I had never been to. We’re at the end of day three and he still can’t figure out what’s wrong with it! He started with replacing the glow plugs, then the relay, then the 15amp fuse, tomorrow the fuel filter. Four days and still clueless. Anyone have any other idea?
I love my car and have only had one other costly fix in the 8 years I’ve owned it.