Car Stereos: amp cuts off at high volume, poor air circulation, ohm load

Question
Hey man, whats up.  I have a four channel amp coming from two infinity rear speakers and bridged to a 100 watt sub.  Whenever i turn my stereo up to reasonably high volumes for a short period of time the amp cuts of and on until i turn the unit down. I have re-grounded the amp in several areas.  My only thought is that my car is a 1990 cavalier and the alternator is just weakening out, or the fact that i used 12' of generic 8 gauge house wire to power my amp.  How can i solve this?

Answer
Joe, Normally, an amp cuts out at higher volumes when it gets hot.  There are a couple of reasons for this.  First, and most common, is poor air circulation around the amp.  If your amp is in a tight space with minimal air flow, it should be moved.  Second, The ground wire is not large enough or attached properly.  The ground wire should be as large as or larger than your power wire and as short as possible.  Third, it could an impedance issue.  If your sub is wired to your amp and it is 4 ohms, then your amp must be able to handle a 4 ohm load in bridged mode.  Also, when you bridge two channels into one, that is done through the amp.  There should only be one positive and one negative going from the amp to the sub.  One of these is your problem.  Check it out, and your problem should be fixed.  A weak battery or alternator, or voltage drop from bad wire; will not make the amp cut out.  It will just not play as loud.  Hope this helps, Scott