Bleed over in a Volvo

I switched companies and I'm rolling in Volvo. I run a Striker 486 or some number close to that with a Wilson antenna on a Volvo perch mount. SWRs are 1.3 to 1.5. Problem I'm having is bad bleed over through the stereo system. The stereo can be off and still get the bleed over. I've run an inline filter on the CB and nothing. Turned the mic gain down..nothing. Turned the CB power all the way down and the bleed over subsides but I'm not be heard and when I say that I mean the guy parked 100 yards behind says I'm coming in very very low. I'm going to attempt running better grounds in the morning on the CB but want to see if anyone has a better solution or has had this problem in a Volvo and what they did to correct it.