Code 13, 14 and 52

Okay. So here is the information on those codes that we have:

13 - Intermittent loss of RPM signal - Probable cause is a bad distributor or the connection to the ECM.
14 - Intermittent loss of ignition signal - Probable cause is a failing ECM or the connection to the ECM
52 - Knock sensor - Probable cause is the ECM or connection to the ECM.

So, check the connection to the ECM. Attached, you will find ALLData's how to on removing and reinstalling the ECM. What you want to do is pull it and check the connectors for corrosion, gunk/crud, and looseness. Clean them up and reconnect them. Put everything back together and you should be good to go, if that is the problem. Let us know how it goes.