Trouble codes

The initial four codes you report are not valid codes on the 2000 Sonata. I suspect there's a communication issue with the code reader you're using.

This car doesn't have any networked communication system, so any code beginning with U can be dismissed, and presuming you're checking the engine control module, there should also be no C (chassis) codes. Those would be in the ABS/Traction system.

Also presuming you're looking into a check engine lamp and lack of power/misfire, look into the P0301 with normal diagnostic procedure. Unfortunately, that's the cylinder on the passenger side at the firewall. Usually, the problem is with the plug or plug wire.

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Hmmm... I am not using a "cheap" reader.. I intentionally did not cheap out on the reader for this very reason...

Yes, I am getting a check engine light, with a definite miss, and loss of power.

I purchased a new set of plug wires and plugs already, so I guess that I will start there.. How bad is the procedure to access the firewall side plugs? Is it one of those disconnect the motor mounts, and roll the engine forward routines?

me

You won't have to move the engine forward, but depending on your perspective, it could be better or worse. There's more to disassemble, but once the plenum is out of the way, the plugs are very easy to access.

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