Ford Taurus spitting and sputtering occasionally but always uphill sometimes at stop lights

2000 Ford Taurus V6 3.0 Dual Overhead Cam 24
valve I have spitting and sputtering going up hills
every once in awhile on the highway and a lot
through town and occasionally at stop lights and
stop signs PVC valve and hose has been replaced
and the crankshaft breather hose has been
replaced to still does the same what else could it
be? It's not too bad but it's bad enough to piss you
off seems to drive better on the way to work then
on the way home only 115,000 miles on the car
and extremely good shape and when running
correctly runs like a brand new car