Audio Systems: 98 dodge grand caravan infinity speakers, dodge grand caravan, infinity speakers

Question
I have a 98 dodge grand caravan ES with the infinity system.  I recently put in a 180 watt VR3 system, using the standard wiring connectors sold at an autoshop.  Everything went fine, but when I turn the volume up higher (or there is a lot of bass), the speakers cut out.  This also happens when I turn on the loud feature on the stereo.  

Can you help me determine what the problem is?  Other than the system is working great.

Answer
Don't turn up the volume , i know it sounds good but you are about to blow the factory infinity amplifiers
the factory infinity radio is only 1 watt per channel the power comes from the factory amplifier,

your new radio is 45w per chnnel to much power  
you need to install this interface  after the new radio

http://www.oemautosound.com/pc-598-148-oem-interface-differential-converters-uni...