Many times, when other fixes have failed, it becomes necessary to eliminate the ECU to harness connections as a cause. This requires removing the ECU. Up under the dash, to the right of the steering column is the ECU mounted to a black bracket. The bracket is held in place by two 10mm nuts to the underside of the dash. It’s most easily removed using a ratcheting wrench but a socket will work.
Once you get the ECU down, unplug the two harness connectors from it. Visually inspect the connectors and pins.
Using a good quality electronics cleaner, liberally spray both of the harness ends and the ECU pin area.
Now, take a small pick or a dental tool and go to the harness connectors. Using the tool, tweak each female receptacle in the harness plugs so they will grasp the ECU pins more tightly.
Plug the harnesses back on to the ECU and reinstall it.