99 ford windstar wont idle it chugs and dies, replaced IACV, EGR, and MAF, still no luck any other ideas?

having problems with our 99 ford windstar 3.8 liter. It will drive just fine when on the road, but when it is at an idle it runs real ruff and dies. we took it to auto zone where they put it on a diagnostic for error codes. since the error codes reported three issues we replace them all and still no luck. we replaced the MAF, IACV, and EGR valve. does anyone have any other ideas? The only thing it seemed to solve was the check engine light.