How to boost FM signal?

There is some sort of power amped ant in your car. are you powering the blue wire on the aftermarket harness?

Honda mostly used standard ones untill '05. But for whatever reason there is 2 chances are one is made by delphi. witch would use a smaller one

2’2" - 2’ 8" will work from 108Mhz-88Mhz as long as it is reflecting on your car.