Engine Performance problem
1997 Ford Ranger 6 cyl Two Wheel Drive Automatic 160000 miles

My 1997 Ford Ranger (4.0L,V6) stalls when coming to a stop or when idling. It is more common in cold weather. Check Engine codes are PO171 and PO174. I have replaced the Mass Air Flow Sensor and the Idle Air Control valve. The PCV valve and hose seem to be fine, as well as other vacuum lines. Any other ideas?

intake manifold gasket
leaking
check it out
good luck

Need a tool or a tester CHECK IT @
http://www.2carpros.com/affiliate/uid/bmrfixit_1
need manual CHECK IT @
http://www.2carpros.com/kpages/auto_repair_manuals.htm