Simulcast distortion can sometimes be cured by moving the antenna to find a sweet spot that works best. Sometimes it is just a small relocation that is all that is needed.
If you have an outside antenna it might actually be too efficient, try using the attenuator. What happens is that your radio is getting signals from 2 or more of the sites and they tend to cancel each other out. If you can force the radio to hear just one site it usually works better. A directional antenna often helps but you can sometimes reduce the effect of simulcast by tilting the antenna, reducing the length or using a reflector.
It is more an art than a science it seems.