Working on a 2005 Hyundai Sonata with the 2.7 litre V6. Car had sat for about a year and a half without being started. Had to remove the gas tank for a flush. Blew out the pressure and return lines. Replaced the fuel pump and strainer. Started the car and it coded a misfire on cyl. #s 1 and 4. I replaced both injectors and all spark plugs. Coil pack and plug wires are good. Now the car runs better at higher than idle speed but idle is rough and it has coded again, P0271 indicating a high current to or in injector #4. I suppose I could have gotten a bad injector from the parts store but what else can I look for to diagnose the problem? Thanks.

 

Swap injectors number 1 and 4 to see if it follows the injector

 

Swapped injectors and the problem remained with #4. I do not have the capability to check the controller so I'm probably going to have to take the car to the dealer. Thanks for your advice.