Cassette adapters for car audio for ipod

I would hazzard the guess your cassette player's auto-reverse mechanism is trying to do its job; it senses tape is not moving, so its trying to switch the transport direction. Try removing the cassette adapter, flipping it over, re-inserting it "upside down" compared to the original configuration, and see what happens. If that doesn't help, try a different brand adapter - they're cheap.

However, its also possible your vehicle's cassette deck is incompatible with playback adapters ... relatively rare, but not unknown. Unfortunately, the higher the overall quality of the head unit, the more likely it will be incompatible with most playback adapters; higher cost, very sophisticated cassette playback systems can't be fooled into "thinking" tape is moving when no tape is present.