power problems

[93gagt_red]

i have a 1993 grand am gt with a 3300 and i just bought it and I am wondering if this sounds normal when i got it I would turn on my headlights, wipers, or when my factory radio hit hard the volts on my gauge would go from about 14 down to about 10 and when i turned my turn signal on every time it flashed the power would flusuate so I took it back they put a new battery in it and it still did the same thing so they put a junk yard altanator in it and it didn't change the problem so now i have bought a brand new on for it and now it goes form about 16 to about 12 can any one out there help with my problem?

[cutlassboy_2001]

Have you tried to change your M.A.P. sensor? I have a 93 that was doing the same thing and all I did is changed that sensor and now it runs top notch