Is this a air ratchet or impact?http://kalamazoo.craigslist.org/tls/3134360840.html
Probably not. Most likely max torque of about 100ft lbs. So it may remove some on smaller imports, but if their seized it a no go. there are very few 3/8 impacts that can provide the torque necessary for lugnuts.
Either my IR Titanium or Snap-on MG325 will break loose any lugnut up to an F250 sized truck without a problem.
The snap on MG325 is one of the few that i was referring to.