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The Echo must be a 2000 That was the first year. The filter is in the fuel tank. Click on the link below for an exploded view of the tank and location under the seat for the fuel tank bracket and pump assembly.
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If you look at the picture it shows the fuel pump filter right in the picture second piece down on the right just above the fuel pump. It is incorporated into the fuel pump housing. The whole assembly has to be removed from the tank and disassemble and the filter portion can be replaced separate from the whole assembly.