Jolting when accelerating

I have a 91 bronco 5.0 and i think it might have electrical problems but im not sure. Usually when i start it up i will notice that the battery gauge is closer to drained but it is brand new. When the gauge is down when i go to accelerate the truck bucks. At first i though it was the trans and everything is just fine with it. I can shut if off and it will fix it but a couple time it was running just fine and then the gauge went down and started bucking when i started from a stop but then stopped a few moments later. Like i said i think i might be electrical and if it is or if it isn't i would like to figure out what is wrong. I have put 1000 into it so far with tires all new break lines and new gas tank and just want to get it fixed so it a reliable truck.

I have a 91 bronco 5.0 and i think it might have electrical problems but im not sure. Usually when i start it up i will notice that the battery gauge is closer to drained but it is brand new. When the gauge is down when i go to accelerate the truck bucks. At first i though it was the trans and everything is just fine with it. I can shut if off and it will fix it but a couple time it was running just fine and then the gauge went down and started bucking when i started from a stop but then stopped a few moments later. Like i said i think i might be electrical and if it is or if it isn't i would like to figure out what is wrong. I have put 1000 into it so far with tires all new break lines and new gas tank and just want to get it fixed so it a reliable truck.

Ok well i think i figured it out. When the battery gauge would drop down i would get the jolting i noticed that everytime that i turned on the rear defrost that the battery would drop and that is when i had the jolting. So i think there is some sort of short in the line but im still trying to figure out what you be making it jolt. Could the short affect the fuel pump and make it jolt.