Harness problem on '93 240

[Sam]

Is there a known problem with the harness or the computer of '93 240?

I had the AMM and the coolant temp sensor replaced, but still get code
1-2-1 and 1-2-3 occasionally. Unplugging the battery seems to solve
the problem for a while.

 

[G Klein]

For 121 make sure that the coil wire is not touching
the maf sensor harness