Check ingion light code p303 whats wrong and how do i fix it the thermostat was just changed and the light will not go out

if you cleared the code - fixed arc and checked their are no more arcs - and keeps coming back then problem can be a burnt or carboned valve --lifter -push rod --piston

Those P300 codes are cylinder misfires
from bad COP Ignition Coils

Go to : http://www.obd-codes.com/p0301
Let me know if this helps.
Terry

I don't think it is your catalytic converter because your light usually flashes and a bad cat I never heard of them causing a misfire. I ran your other code it is for a faulty EGR system. Exhaust gas recirculation excessive. You are getting too much exhaust gas back in the system. This will cause your misfire. Go-to a trusted mechanic and have them check out your EGR system.

code says #3 cylinder misfire, check the coil pack for this cylinder to see if its got spark, bad o2 sensor will spit another code, its most likely the coil

P303 = Cylinder 3 misfire P0734= Gear 4 incorrect ratio 0745= Pressure Control Solenoid A
Not sure if you just wanted to know what the codes were, or how to fix them hope this helps

Reset the computer.

Did you ever do a tune up? If not you need to change the spark plugs pvc if you have one,some do and some dont anymore.also change the spark plug wires.This is where you have to start,even if your car was in a shop.Then you go from there if this does not fix your problem take to a good repair shop.

p303 is a cylinder 3 missfire I woul first check the coil and then the ingnition module, Then if this dont work you could have a bad injector. If after testing and still no fix you should check the compression in that cyl.

http://www.kiatechinfo.com/index.asp

Good source for Kia its free to register NO STRINGS