Dakota Too Fast Idle

I recently replaced the 2.5 l. in my 95 Dakota and am still working out the bugs on it. I have replaced the IAC valve,temp.sender, new plugs,wires and vacuum lines. It showed 17 inches of vacuum when I checked it. The idle is too fast and it tries to die when I come to a stop. It showed a code 44 when did the key check for the computer codes. Does anyone have any ideas where the problem is. I did not want to replace the computer if it is another problem. Also the gas mileage is only 17 mpg.