I have no idea what those last two are. Typo, maybe?
Your first two codes could be caused by old spark plugs and/or leaking plug wires.
Your EVAP code could be a bad fuel tank pressure sensor or a malfunctioning EVAP system. With that code, if you remove your fuel cap and get a whoosing sound, then it is an issue with your EVAP system not properly venting the tank. If you don't get that sound, then the tank pressure sensor is bad.
Have 2000 Saturn LS2 with 3.0 engine keep getting multiple misfire code in cylinders 1, 3 and 5. Changed coil on plug pack. Changed spark plugs and fuel injectors. Still getting multiple misfire codes. Engine seems to run fine, but when sitting at light idle seems low at 600 rpms.
Answers & Comments
P0300 Multiple Cylinder Misfire Detected
P0306 Cylinder 6 Misfire Detected
P0451 EVAP Pressure Sensor Range/Performance
I have no idea what those last two are. Typo, maybe?
Your first two codes could be caused by old spark plugs and/or leaking plug wires.
Your EVAP code could be a bad fuel tank pressure sensor or a malfunctioning EVAP system. With that code, if you remove your fuel cap and get a whoosing sound, then it is an issue with your EVAP system not properly venting the tank. If you don't get that sound, then the tank pressure sensor is bad.
The evap is likely to be the cause of the misfires too.
Have 2000 Saturn LS2 with 3.0 engine keep getting multiple misfire code in cylinders 1, 3 and 5. Changed coil on plug pack. Changed spark plugs and fuel injectors. Still getting multiple misfire codes. Engine seems to run fine, but when sitting at light idle seems low at 600 rpms.