Just an update.

There are several kids in the neighborhood that work on cars and borrow my tools. This time they loaned me the tool. I used a Milwaukee Fuel 18V.

I was very impressed, it took it a few seconds but it pulled the bolt.

I dodged a bullet and didn't have to buy one this time but I will be getting an electric impact. Even though the Milwaukee has better specs I am leaning towards the Dewalt because I have a lot of Dewalt and a couple Craftsman battery tools. I just don't want to have to have multiple tools that don't use the same batteries.

Thank you all for the advice. Had I not asked I would have bought an air impact and I will definitely get more use from the battery powered one.