If you want to convert to EFI from carbed you will need the inside harness from an EFI vehicle. That involves removing the dash and removing the old harness and installing the EFI harness to match the external connectors. Yes, they did make EFI 2.3 in 88 and yes you can make the switch...and it's not really that difficult...
It would be best if you could get the inside harness and computer from the same year Ranger that you got the outisde harness from...they are all pretty much the same...
I have been contemplating the same thing for about four years now but the carbed version of the 2.3 works almost as well as the EFI with half the headaches of extra sensors and fuel lines. You may need to, as in my case, install an electronic low-pressure fuel pump if the 2.3 block does not have a manual pump on it. You don't need to change the gas tank or add return lines.
If you want to make your life even easier, try to find an earlier 2 barrel carb and intake so you can do away with the emission controls that the 2.0 has...the 2.0 emission setup is not worth the trouble to try to get it right...my carb came from a 78 Mustang 2.3 and it made a world of difference...there are other options as far as carbs go, but buying a new carb and adaptor and paying $500 was not an option for me...although a 500 CFM or 350 CFM Holley carb is tempting right about now...
