Check Fuel Sub Level Sensor

Remove the fuel sub level sensor. 

Measure the resistance between fuel sub level sensor and terminals with its float set to the full position.

Terminals 

No. 1 - No. 2: 

Is the resistance 0.5 - 2.5 O? 

YES 

Repair poor contact in harness between ECM and combination meter connector.

NO 

Replace the fuel sub level sensor.