too much power car running bad.

Here is what I got :

2002 Dodge Intrepid, 2.7 litre V6 with oem 140 amp alternator.

Massive P3000.1 mono amp rated at 3000watts.( inline 200 amp fuse recommended)

Massive P800.4 4 channel amp.( 60 amp fuse )

4 farad cap.

one gauge power wire feeding two "yellow top" Optima batteries.

All grounds and alternator wires " stiffened"

MY PROBLEM IS WHEN I'M CRUISING AND HAVE MY STEREO PUMPING MY CAR PERFORMANCE GREATLY

SUFFERS , NO POWER, ROUGH IDLE AND STALLS AT TIMES.

WHAT WILL CURE THIS PROBLEM.....DO I NEED A BIGGER ALTERNATOR?...MORE BATTERIES?

HELP PLEASE.......

The additional battery is causing your alternator to struggle to keep up.

First things first, if the performance of the car is suffering, do NOT drive the car with your stereo up.  It is possible for the vehicle to stall which could be dangerous, especially at higher speeds or if you happen to be approaching an interesection.

If you have a 140A alternator, and you have added 260A of audio 'extras' it is easy to see where your problem is.  Typical OEM loading of an electrical system is ~75% under full load.  So, we'll give your car the benefit of the doubt and say that the car requires 70A of power while you are driving it.  If you add the 70A to the load your amps are actually pulling - say 200A - and you need at least 270A to keep the car happy.  As I'm sure you know, 270A is MUCH more then 140A.  There are only two ways to fix this problem 1. Get a bigger (or additional) alternator and 2. Get smaller amps.

No amount of additional batteries or capacitors are going to help you, your car simply isn't making enough power to run.

Another thing to keep in mind is that low voltage situations can be very rough on electrical components such as TCMs, BCMs, PCMs, ECUs, your alternator, your battery, and your audio amps.  If you continue to abuse the electrical system there is a chance you will fry a critical engine control module.