1999 Saturn SL1 Engine Misfire

First of all thank you so much for your donation. What rpm does your car idle at when it's all warmed up?The P0507 and the P0301 could be related if you have a vacuum leak on the intake gasket at the number one cylinder. The P0341 is usually spark plug's and wire's that have black carbon build up on them.I would take the plug wire's off the plug's get a bright flash light and see if you can see any black carbon build up on the spark plug wire end's of the boot's where they attach to the plug wire's. Also check the plug's themselves for black carbon or pitting where the spark plug wire meet's the plug that is a good sign there is carbon build up. Also does the engine idle smooth or can you feel it miss?