mine is a 2.7 liter. i am not sure about the 3.0. on the 2.7 it was under the car right behind the from exhaust manifold. i had to access it underneath. remove the air filter, front motor mount, catalytic convertor and the heat sheild surrounding it.

 

It should be near the front, passenger side. See if you can get it to turn over by jumping the posts as Master tech mentioned. I removed mine and had it tested. It "tested" ok at AutoZone, but it was a bit hesitant. I replaced it anyway as I was 99% sure that it was my problem (battery was good and charged).

To remove it, I only had to remove the sensor that screws into the exhaust manifold. FYI...that sucker was in there tight, be careful when wrenching it out. Also, cover the end with a clean rag while it is out. My car ran a little rough afterward and I figured I got a little oil on the sensor. Its all good now.

 

Thanks for the response Alpine, do you have a diagram that i can use as reference? I don't see it.