I have a random misfire code. But if you watch it on a scan tool its only the driver side usually cylinder 1 and 3. I have replaced all 8 plugs and wires. I have replaced all 8 injectors, and i have replace the coils for cylinder 1 and 3. The truck still only misfires. But it only misfires after you have driven it for a while and you shut it off then restart it. Pretty much your tipical gas fill up is enough time for it to misfire when you start the engine back up. But if the truck sits long enough it will not misfire or if you take it up the road and beat on it a little it will clean out and run fine until the next time you shut it and start it back up quickly. What could it be? The only other thing i could think of is that the cat is getting plugs when it gets hot and making the engine miss. But that still doesn't explain why it only does it after you shut it down hot.
Engine misfire on 2001 Chevrolet Silverado 2500 HD
CHECK THE FUEL PRESSURE REGULATOR. PULL THE VACUUM HOSE OFF. IF GAS RUNS OUT THEN REPLACE REGULATOR.
lots of problems with the cat causing missfires. have a shop check your cat for failure. there is a left and right cat and can be replaced separately.