I can't trace the problem. 2008 impala ltz 3.9 161k miles

Hi! This is Bo with Car Genius at RepairPal! Oh no! Not with a car you just got! It could be so many different issues. I'd start by checking for any codes stored in the car's computer. That might point you in a direction to start. It may be a bad MAF sensor which would cause the air/fuel mixture to be off. Maybe it's a dirty or failing throttle body? The best thing would be to get it to a trusted shop in your area for diagnosis. If you have any other questions feel free to call us at 877-913-1554! We'll be happy to find you a certified shop in your area!