Fault code is P0183

Hello
The engine and transmission in this cars drive train are fully electronically controlled by a computer called the PCM (Power Train Control Module). Whenever a problem like this occurs the computer stores a record of the problem (there are of course some exceptions to this, like the fuel pump, engine coolant temperature sensor and MAF sensor for instance) in the form of a fault code in its memory, to read these fault codes you must have the systems memory scanned with a special tool. Once the fault code(s) are read you then must perform the appropriate diagnostic testing to find and resolve the problem(s) DO NOT REPLACE ANY PARTS UNTIL A TRAINED TECHNICAIN HAS DIAGNOSED THE PROBLEM TO AVOID SPEDING YOUR HARD EARNED MONEY ON PARTS THAT MAY NOT CORRECT THE PROBLEM

you can try to read the fault codes with ELM327 V1.5 scanner, and know where is the problem, and then you can fix the problem. It is cheap and easy to operate.

You'll need someone with a code reader - scanner.
Most auto parts stores in the USA will scan for free in hopes of selling you a part.

check the air intake hose for cracks between MAF sensor and the intake. very common to crack underneath and cause the engine to set various engine codes.

could be oxygen sensor , or loose wire on oxygen sensor.

Take the car to Autozone and ask them to read the error codes stored in your 'on-board diagnostics' module. They will do this for free. Autozone may advize you of what the code(s) mean but if not go on-line and search using "error code P**** KIA" and this will elaborate the fault in greater detail.

Firing order 1.2.3.4.5.6
Looking at engine , number 1 cyl left front,number 2 left middle,3 left back
Number 4 right front,5 middle right ,6 back right
Fault codes indicate missfire cylinder 2 and 6

SOUNDS LIKE A CATALYTIC CONVERTER.... BUT GO TO YOUR LOCAL AUTO ZONE OR YOUR PERSONAL MECHANIC AND HAVE HIM DO A OBD SCAN IT WOULD TELL YOU ALL THE DEALER FAULT CODES.... AUTO ZONE IS FREE LOCAL MECHANIC AT LEAST $250 FOR A 10 MINUTE PROCESS

This is a common problem usually related to the crankshaft position sensor. Before you replace it, disconnect the electrical connector to the CPS sensor and clean it with electrical contact spray and add a dab of dielectrical grease. If the problem continues, replace the CPS sensor. It is easy to replace and is not very expensive. It just bolts to the engine block with one or two bolts. I believe the CPS sensor on the Sedona is behind the timing cover on the front of the engine.

This is the KIA tech site. Free to register and use. It lists the repair tech manuals, Sevice Bulletins,Trouble Code identifications, How-to's, and troubleshooting guides the factory trained repair guys use:
http://www.kiatechinfo.com/index.asp

AutoZone will read trouble codes for free