2000 1.9TDI 110 SOUNDS LIKE TIMING BELT SNAPPED

[mercedes190d]

HI LOOKING IF ANYONE HAVE HAD THIS ISSUE
start car rev and only random will cut out and when try to restart gives the distinctive noise if timing belt has snapped which it hasnt and will turn over for a while and then fire up and wont happen for a week or 2 and do same thing 
any help appreciated
cheers

[EsSeX dAn]

get it plugged it 1st off see what that throws up