have a 04 ford explorer xlt an my fuel gauge wont raise to full after I just filled up my check engine or my check gauge light isn't coming on so what could be causing it not raise to full

 

Until you can first confirm that the connections from the sending unit in the tank up to the gauge are good, the sending unit usually is suspect. Some gauges can take a little while to stabilize and will read correctly afterward.

 

Same issue my daughter had with her 2004 Explorer. It just may sulfur contamination of the wire wound sensor/lead wires. Chevron's Techron Plus is great for cleaning the fuel level sensors/contacts of sulfur deposits. I would try this before tackling wiring and connections and it's easier. The Techron cures hers.