Good afternoon, Gentlemen. I'm working on an 81 304 4 speed with the CCC. So far, I have replaced: Plugs Wires Cap Rotor Ignition module EGR valve Air cleaner temp sensor Carburetor All vacuum lines Now until 2 days ago, I could start it up, it would go right to idling at 600 rpm solid, regardless of engine temp. Once it warmed up and the heat riser valve & choke were open, it would drive fine. Then two days ago, I started it and it idled up to about 1200...then 1500...then 1100...then 700...then 1200...if it gets close to 600, it begins to stutter then revs back up to 1200...then 1500...you get the picture. Shut it down, checked all my hoses, wiring, etc. I had forgotten to reconnect the TPS plug, so I thought this was to blame. No dice, same symptoms. Let it sit overnight, fire it up, runs fine! Right at 600 rpm...the just died. Suddenly, no sputter, just plop. Then crank no start, not even firing. I checked codes, I get a 23. So I manually test the mixture solenoid, good solid clicks when 12v applied to the pins. 21 ohms resistance across the pins. In any case, it's a newly refurbished carb, no reason to suspect a defect...yet. I verified beyond a doubt that the fuel pump is working (ran pipe into a jar and cranked, good solid flow right away) and the filter is not clogged. I cleared the 23 code (yes, I get 12 code 3 times first), then ran the car again, it ran erratically, but I got it to stay on long enough for the 23 code to come back. I do NOT hear a repeat clicking of the mixture solenoid when I turn the key to on (not all the way to crank), but I do hear a rapid clicking of sorts when in diagnostic readout mode. On one occasion, I got out of the car with the key in the ignition, still on, but not running. Suddenly the clicking began with no action from me. So at this point I suspect the CCC (ECU, ECM, whatever). It is 40 years old and just got woke up from a 14 year nap. Sometimes I start it and it's all normal again, but then will just die after 15 seconds or up to a minute. Then I let it sit and it just goes nuts again. Sounds like the kind of mayhem only a computer can achieve. I have a reman unit on the way, they're cheap enough, but is there anything I'm missing? I will do the O2 sensor as well before I get the new ECM. PCV valve is not stuck, but I may as well do that too. I appreciate any advice or experience you folks can share.