I can't believe you posted this in September of 2015 and nobody has responded to your question.
The only plug and play engine you can buy for your truck is a 2001-2002 2.3 Duratec.
A 2003 will work, but the salvage yards won't sell it to you unless you acknowledge that you're taking a risk. For some reason they say a 2003 2.3 DOHC is different than a 2002. In 2004 Ford eliminated the intake runner thing with the butterfly flaps.
And good luck finding a 2001.5-2002 because they're very rare and the going rate for a used one is $1100!
I have a black 2004 Ranger XLT 4X4 4-door extended cab with a 4.0 SOHC, 5-speed manual transmisson and 06+ chrome mirrors. #2 A 2004 Vista Blue Ranger XLT 2WD 4-door extended cab with an auto trans, chrome 06+ OEM running boards, 2006 front end, 06 + color keyed mirrors with a 99 cab that has all 2004 and 2007 interior parts.