ECM trouble codes

Where can I get the trouble code (Check Engine light flashes) list for an '85 Chevy Celebrity V6 2.8L MPFI? Seems it should be available somewhere on the web, but I can't find one.

Present situation: Upon cold start in ambient 75 degree temp, engine rough for first two or three minutes; then as it beings smoothing out, the Check Engine light begins flashing codes 12 and 52, and the idle gradually increases until the engine is racing and needs to be turned off.

Temp-related, but it seems to occur too soon for the coolant temp to be involved. Exhaust temp or O2, I suspect, but I don't want to begin dismantling every sensor without a better clue, such as a code interpretation. After all, that's what they're there for.

Yesterday, I was getting a whole medley of codes (12 - 24 - 44 - 52 - 54) but they settled down to 12 and 52 after disconnecting battery to clear ECM memory.

Really would like a complete list of codes. Anything you can provide will be appreciated.