try replacing the idle air valve or clean it out, some guys drill a 1/8 hole inside that idle air valve, on the 5.0s though.. hmm never had problems with high idle,,,havn't had my engines throw a code yet, would like to convert one to carb one day using the stock roller cam from a 91 stang on a 87 block, did you notice a big power change with the roller cam?, all my 2.3s on the road are not rollers, i do have two roller cams setups on the shelf,,, hey a good site for 2.3 engine buildups is www.4m.net under the ministock racingtech section,, lot of 2.3 dirt racer buildups, lots do the carb conversion using the 2.3 efi intake, just adapt a carb spacer plate, sure nice to get away from all the computer sht, most run a 350cfm two barrel carb