I think the firing order on any GM V-8 is 1-8-4-3-6-5-7-2, #1 being the front cylinder on the drivers side and #2 will be the front one on the passenger side, then back to the drivers side for #3 and so on.
RepairPal Certified shops can diagnose and repair your 2006 Chevrolet Impala. They provide transparent pricing with a minimum 12-month or 12,000-mile warranty on repairs and services.
The diagnoses said it is my #1 piston has a misfire