Ok here's the story. We were under the hood changing a hose due to it leaking coolant. We noticed that the throttle body's water connection was weak and it broke off. So we bypassed the coolant line in the throttle body. The car drives fine, engine is running cool but when I do two things at one time (turn on the lights and air conditioner, or turn on the lights and use the power windows) the RPM will jump like crazy. My car cut off on my at the light last night after running the heater on full steam with the lights on. Could this be just a weak battery or another issue? I wasn't with my uncle when he bypassed the throttle body, but he's extremely experienced and knows what he's doing. I don't think he disconnected the battery at all while he worked on my car. I just disconnected the negative terminal and I'm going to let all the juice leave the car before I hook it back up and let it run for 30 minutes. Any advice or insight would be greatly appreciated.

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