Bad starter or bad battery for Buick lacrosse?

pumping the gas on fuel injectected cars does nothing. I would guess fuel pump.....you need about 40 psi or more for fuel injection, if the pump is weak you are not getting enough gas to start the car. You can borrow a fuel pressure tester from AutoZone and other auto parts stores

These cars act really goofy when the battery is going bad - mine exhibited very similar issues when the battery was failing, plus I can't think of any good reason why the car alarm would go off if it was a bad fuel pump. Sounds more like behavior exhibited by a car with a dying battery or loose connection. For anyone reading this, the battery is definitely the cheaper place to start and should certainly be considered a suspect if you're seeing behavior like this. I assume the original poster meant "filling the fuel tank with gas" - they shut the car off, fill the tank, and then the car won't start when they get back in the car to leave.

To continue... Yes, this could also be symptoms of a starter that's failing and drawing too much power. Starters and batteries can both be tested to determine what is at fault.

My car had the same problem starting and cutting off took it to the dealer their diagnosis was the Body control Module for the Buick Lacross 2012. That was not the problem and that was the dealer I bought the car from, Crystal Auto Mall. their service department messed me up because even when I bought the new part the car still did not work. Knowledge, the car has 3 modules the Body Control Module, the Engine Control Module and the Transmission control module. Each computer control that specific part of the vehicle. I've learned a lot because it cost me a lot of towing fees and the 3rd garage fixed my car, a Buick, GM shop in sunny side queens. if your car has a computer component make sure you use original parts and the entire car has to be working together as a whole. I hope this info was helpful.