2007 chevy impala 3.9

Hello, my name is \*\*\*\*\* \*\*\*\*\* thank you for using just answer. The site will prompt a phone call, but that is not always necessary. If it is necessary later in the conversation, I will propose it. I am sorry you are having this concern, but I will do my best to assist you. What kind of scanner are you using? What is the mileage on the motor? Thank you. Kyle S. A.S.E. certified master auto technician licensed smog technician, test and repair, L-1 advanced [engine](/topics-engine-chevy/) performance certified Certified Volkswagen technician, 2003,2004,2013,2014,2015 Volkswagen and Audi independent 12 years

Can remember the name of it don't have the scanner with me nowIt's a 2007 chevy impala 3.9150000

Ok. How are you verifying which cylinder is misfiring? I would be using a scan tool for that, but you can also do it manually by shorting out a wire or disconnecting an injector and listening to the amount of rpm drop. Given the mileage, a compression test would not be a bad idea, to make sure the engine is mechanically sound.

It said cylinder 5 on my scan tool

Ok. A good scan tool can watch the individual cylinders in real time for misfires. If your tool does not do that, I recommend you start with a compression test of all cylinders.

Could overfilled oil cause a misfireCould over filled oil cause a misfire?

Not unless it is heavily smoking.