Car Stereos: Amp, speaker wire, subs

Question
I recently switched my amp from my car to my truck. The subs worked good in my car. Now that I switched the amp and subs to my truck, the subs don't work very well, and the amp makes a weird whining sound. What can I do to fix the whining sound?

Answer
I have a few questions for you.  

What kind of wire did you use to install the amp.  What kind of speaker wire did you use?  What side of the car is the battery on and what side is the amp on?  What kind of truck is it?  What kind of speakers and what kind of box?  Let me know.  Thanks!


Dave