you did replace maf?? if not try taking it apart and clean it..if it
works then you know it'll be maf..i cleaned mine lasted 6 months and i
finaly bought a new one and how long ago did you have plugs and wires
changed??..good luck..

   Bad plugs, fuel filter, partly-clogged cat convertor, bad plugs (Yes,
even new ones!) weak fuel pressure, water in the fuel, improperly-set
timing, partly collapsed exhaust pipes, bad wires breaking down under load,
EGR valve--and other.  You may wish to tackle the problem with what seems
more logical to you.  With such low km on a 2000, it quite well could be cat
conv (not cheap; but if bad, check on Ford's warr on emission systems: may
still be under warr) as often low-km units have been subjected to lots of
short drives & home-to-grocery store runs--running lotsa rich fuel thru
exhaust system.  Only you know how old plugs, fuel filter(s), wires are.
Remember: the 'real' cost of GOOD ignition parts is not what you have to pay
for them--it's only the DIFFERENCE between their cost and inferior ones'
cost!!!
   If you look at the wires AT NIGHT, with someone's help, with car in
gear, emergency brake ENGAGED,  and helper's foot on brake and properly
chocked wheel(s), have helper slightly increase rpm's.  If the wires 'light
up' like xmas lights flickering, you can safely bet new wires are in order
regardless if they are causing problem.
   Exhaust problems would probably cause a 'swishing' sound when under load
as the exhaust squeezes thru restricted routes thru the pipes/cat/muff.
   Luck to you.  Ensure a proper, thorough tune-up has been done recently.
This could fix it or eliminate several possible causes.  s