One problem related to tank assembly has been reported for the 2004 Honda Civic. The most recently reported issues are listed below. Please also check out the statistics and reliability analysis of the 2004 Honda Civic based on all problems reported for the 2004 Civic.
The fuel gauge goes crazy for lack of a better term. One minute you're driving and the gauge shows you have a half tank of fuel. A few miles later your fuel light comes on and implies your out of gas. Then when you fill-up, the car only needs a half tank of gas. As someone who does highway driving everyday, this can be unnerving. Someone else who had the problem said a dealer said to fix the gas gauge would be comparable to brain surgery. To go into fix it would probably cause some other problem.