My 2004 buick park avenue has a misfire on plug #5 what do I do
Change the spark plugs & the wires
especially if its over 100,000 miles
A code for a misfire could be a result of insufficient spark or fuel. Either way, the cylinder not firing properly is detected and it throws a code. As mentioned, I agree with Steve. For the cost, I would change the plugs first and see if it goes away.