Really appreciate any feedback on why my 86 305 Tpi 700R4 is acting like it is posessed?!

Start engine from cold, idles no problem, new Tps & Iac set correctly and a new Cts

Continues to warm up for about 5 mins and then the fun starts.

Idle goes up to 1500 and back repeatedly, SES light comes on and stays on, engine nearly cuts out while idle goes crazy and then clears and does it all over again for 3 or 4 mins.

Engine clears and warms up normally.

Pull the codes and get a 51 and a 42, but sometimes the SES light won't light up when I put the paper-clip in and turn on the ignition although the fan starts?

When fully hot the engine pulls strong & smooth.

I only get the problems when starting from cold.

Do you think I could have an ECM/PROM problem?

Any ideas Guys?

Thanks for reading my message.

 

42 EST electronic spark timing - send signal to ECM to calculate timing advance

51 MEM-CAL this is the part where the chip snaps into. the MEM-CAL controls the ESC(electronic spark control). now, seeing as how sometimes the SES light won't come on when you jump it, then its possible you have an ECM failing. the MEM-CAL is soldered to the board. it's possible the solder is coming loose. check there.