I have a 2000 Silverado 1500 4.8L with 95,000 miles. Iíve been having problems with misfires in several cylinders. I replaced all wires and plugs. Iíve been told that I need to replace the ignition coils on cylinders 1, 3, and 5. What is the placement of cylinders 1, 3, and 5 for this engine? Is there any other reason for misfires?