Well the "timing thingie"

, is the EST. The ECM controls the timing via EST , so that when your engine overheats it retards the timing for safety measures. Or it will bump the timing in certain cases. If you don't disconnect the EST you will have a hard time adjusting the timing it will bounce around because the EST is constantly adjusting the timing especially while you are not moving. That can in some case (Ive seen this before) where they thought the erratic timing was the timing chain so they spent $300 dollars to get it fixed when all it was , is that they didnt disconnect their EST , also if you have a manual adjust timing in neutral or automatic in drive. Oh ya in latter models such as your 1992 and also my 1992 TPI, the EST should be located near the ignition coil. Good Luck