91 Z28 LB9 auto 100kms

Recently I've been having weird things going on, my electronic speedo is off and then works for a while then off, my elrctric fan comes on when engine is cold, engine either idles fine, low or high.
From a previous post I gather it is probably a bad ground.
How many grounds are there? Where are they and which one is most likely the problem? Thanx

 

There is a ground from the block to the frame at the back near the dist, check the ground from the battery basically anything attached to the frame inspect, clean and redo. From your complaint don't overlook an intermittent internally with the ECM. You might try dropping it down and as you drive it have someone in the passenger(perferably with great legs) seat tap it with the handle of a screwdriver to see if you can generate the problem. Unfortunately with TG's there are a lot of little issues electrically related. Keep us posted.