My Golf 4, 1999 model has a problem of hard starting. What could be the possible causes?

At the under hood fuse box are any terminals burnt ? High resistance is one possible cause , weak fuel pump ,low current flow . The proper testing procedure should be implemented ! Test the battery's open circuit voltage , voltage drop test power an grounds . Videos on you tube showing , basic electrical testing , voltage drop testing .Fuel pressure an flow testing . Wiring diagrams may be found at http://bbbind.com/free_tsb.html .

Slow cranking or cranks fine no start could be several things