On the 3.8L there is only one (1) fuel pump. You need to get an inline fuel pressure gauge and go off the spec listed in the manual as far as what fuel pressure you should have. If it is low, first change the filter and try to blow out the line(s) with an air compressor. After you recheck the pressure and its still low, then get a new pump cause its probably wore out.
If the pressure checks out OK, then move to the throttle body and inspect/replace the injector or a complete rebuild on the TB if needed.
I can imagine with the year of the vehicle that alot of stuff will be out of specs.
Hope this helps!