Hello I need some advice please

I have the 1.9 Tdi 115bhp Avant 2001 model

I suspect the MAF isn't working but how can I check without buying a new one to test?

The car also grounds out alot but my local garage cannot see any fault any ideas?

Finally - sometimes when starting from cold it immediately revs to about 3000 - 4000 rpm but most of the time its fine - again any ideas?