I recently got a P1443 eng light code, problem was the purge solenoid. Used this to troubleshoot http://www.tomshints.com/FordRanger/FR_EPS.htm
Got a new one at NAPA, $43.00. The old one would not close, electrically it was working. I cut the old one open and think it just had some crud in it keeping it from closing. I would suggest if you have this problem electrically open it and spray with a cleaner and blow it out to see if you can get it to seat shut before buying a new one.