That should have been marked on the intake manifold, towards the rear of the engine.
The firing order is correct! However, it has a timing belt, not a chain. The water pump is driven by the timing belt, so replace that while your in there. And Make sure the crank and cams on on TDC before you put the belt on!
diagram for timing marks on 1996 dodge intrepid 3.5
about... well cost of a replacing timing belt is about... £88.93
has a timing chain
In a 2004 Dodge Intrepid : The 2.7 litre V6 engine has a timing CHAIN ( also , the 3.5 litre V6 engine has a timing BELT )
If a 1999 Dodge Intrepid timing chain goes out a valve in the head can easily be damaged.
The 3.5 litre V6 engine in a 2004 Dodge Intrepid has a timing BELT