Okay. So on COLD STARTS ONLY, my car has a lot of trouble starting up. The longer the car has been sitting, the more trouble it has. Once it has been running for a little, it will start up fine. Is this definitely battery?

 

Sounds like it. Take it out and get it tested at auto zone

 

Yeah definitely sounds like the Battery is on it's last leg, sounds like it's a good battery, because it will start, but is it the original battery? or has it been replaced, but I'd say it's 98% a battery issue

 

When I cold start mine the rpms go up and down for a second before settling at idle. Is this normal?

 

Yep, that's normal

 

I think it is the original battery. I wouldn't know for sure. How much is a new battery?

 

well it's an 05 Sedan, so the warranty won't be worth anything at that point age wise,
you need a QB24F from Infiniti you can expect 95-105$ if you were local I'd give you one for about 85$ but I can't ship that
O'Rielly or Autozone will be able to get you one also, either way you are looking at 80+ for a battery, I'd take the one out now, and take it to your local O'Rielly or Auto Zone, or what ever you have out there and have a load test done on it

 

I got a Red Top optima for $107 and I like is isnt the acid base. Advanced Auto with coupons.

 

The walmart Maxx batteries consistent rate best in Consumer reports. plus 3 yr free no questions asked replacement, compared to Autozone, etc where they will always tell you it just needs to be charged.

for 75$ thats all i use in all my cars.
My G35 sits alot, so I just get a new battery every year for it for free. They even give you a new receipt so your 3 years starts all over again.

 

*Fkin dead