2003 hyundai (xg350) 3.5 8700 mil,miss fire cil 1,3,5, long fuel trim,
bank1 rich, long fuel trim bank 2 lean, new spark plugs, new wires ,no vac leak ,good fuel press ,good time belt

It's pretty unusual to have rich codes on one bank and lean on the other. I would be really highly suspect of the 0/2 sensors in this case that one may be reading incorrectly.
About the only other thing that will separate an engine like that is a severe vacuum leak on one side or a bad fuel leak on the other. I would get some new 0/2s in there first though.




78 Corvette Pace Car For Sale-18k mi orig-Florida

thank you for your reply. i switch O2 sensors and injectors with no lock i tried to look on my cats and see if one of them is pluged and i have back pressure.
i really appricitate your help. Thank you

You can't see a plugged cat. You have to read the exhaust pressure ahead of the cat and watch the engine vacuum.
Look for an exhaust leak ahead of the cat that could be letting O/2 into the exhaust and effecting the readings.




78 Corvette Pace Car For Sale-18k mi orig-Florida