My 1989 mustang GT's check engine light is on and it feels a little funny. like when it starts up it runs really good for about a minute then the RPM's sink sorta low and for a second i thought it was gonna die but it didn't... now the Codes are as follows...

Code 13 --- "RPM out of specification during normal idle operation -or- DC motor does not follow dashpot."

Code 24 --- "Air charge Tempature (act) sensor or Vane Air Tempature (VAT) sensor signal voltage is out of specification (engine off) or not at normal levels (engine running) -or- electronic distribulatorless ignition system (EDIS) fault - failure in coil 1 primary circuit

Code 19 --- "Failure in electronic control assembly (ECA) problems with internal voltage regulator -or- RPM too low for EGR check during Engine run self test -or- cylinder identification (CID) sensor input failure.

they all are showing during the KOEO test. (Not Running) and i just don't know what to do to get rid of these codes. i was told but i friend of mine who is also a mechanic that my Coil pack might be bad, a fellow mustang driver said my Distributor cap should be turned to adjust that but i couldn't turn it for the life of me! Can someone verify this dilema for me?!?!?

I've already done/Things to know before you answer
-Distributor cap
-spark plug/coil wires
-spark plugs
-No catalytic Converters
-engine was recently rebuilt but not by me
-New alternator
-New Wires behind dash that were recently broke and frying the other.
-Air Filter Cleaned

Anyone Help?!?!