Rough Idle and Stalling

I have a 1998 Ford Explorer 6cyl. SOHV with 71,000 miles. About 3wks ago it start to idle rough and would stall after stopping. I have had the fuel filter changed, new plugs and wires. New PVC valve, air filter and cleaned the throttle body. I had a mechenic check for vaccum leaks. None found. I also have put fuel injector cleaner in the tank. This happens when it is wet or dry out. What else can I look for or check?

Thank you for any help you can give me.

Randy