P0300 Fault in 2001 Chevrolet Silverado 4.8L: Multiple Random Misfires with Cylinders 4 and 5
I've recently experienced difficulty starting my 2001 Chevrolet Silverado 4.8L when the engine is cold, along with intermittent random misfires. I replaced the spark plugs and ignition wires to address the misfire issue and installed a new coolant temperature sensor for the cold-start problem. However, after these repairs, the misfires have worsened—cylinders 4 and 5 now show significantly higher misfire counts: 1300+ on cylinder #4 and 1900+ on cylinder #5, while the other cylinders register only single-digit values. The OBD2 scanner shows only a general P0300 code with no individual cylinder-specific codes such as P0304. Given this pattern, I'm wondering what steps should be taken next to diagnose and resolve the issue?
As mentioned in a previous post, have you inspected your distributor cap, rotor, and coil pack? These components can contribute to multiple or random misfires. Additionally, faulty fuel injectors—particularly those that are stuck closed—can cause misfiring across multiple cylinders. I recommend checking these parts first as they are common causes of P0300 in 4.8L engines like the one in your Silverado.