IC Tag problems - question

[lornecherry]

...two of my Dnanos, (older cars) skip laps and are thus unuseable with the Kyosho lap timing system. My Kyosho ribbon placement is good, all the other cars are fine and the track is less thick than RCP, so its not the setup — I have confirmed it's only specific cars.

Is it possible to add a core trasnponder or something to the bottom of the car? I really don't want to replace an entire chassis, nor should I have to spend that kind of money every time the somewhat fragile built-in tags stop functioning properly. Cars are not US spec ...so no warranty; just looking for a fix.