99 kia sportage trouble need help from someone that knows kia"s

i am working on a 99 kia sportage and there is 2 issues i have not been able to figure out first thing did a tune up now misfires on #4 did not do before replaced plugs/wires ngk plugs gapped .44 as per kia.going to try new coil pack unless someone knows something i dont let me no please. other issue has engine light on code po452 evap pressure sensor signal low.so i tested vacum on all lines all tested good.called kia on a evap pressure sensor they said they never heard of it.i dont have a manual so not sure what to look for the vehicle ran great with the code and the light but they cant get it through smog.any help or ideas apreciated.oh ya the gas cap tested good and is tight.hopefully i get this figured out thanks

i am working on a 99 kia sportage and there is 2 issues i have not been able to figure out first thing did a tune up now misfires on #4 did not do before replaced plugs/wires ngk plugs gapped .44 as per kia.going to try new coil pack unless someone knows something i dont let me no please. other issue has engine light on code po452 evap pressure sensor signal low.so i tested vacum on all lines all tested good.called kia on a evap pressure sensor they said they never heard of it.i dont have a manual so not sure what to look for the vehicle ran great with the code and the light but they cant get it through smog.any help or ideas apreciated.oh ya the gas cap tested good and is tight.hopefully i get this figured out thanks

replaced coil pack still has misfire going to check injector then compression still have code 452 all vacum lines good so going to try and find a fuel tank pressure sensor that what another forum kia tech said.will let you know what i find

check that compression, I had one at my Kia dealership that had a broken valve spring and that's what caused the misfire. Just something to look for.

hey thanks for the info if it does it again will check.so far i removed the plugs and gaped at 39 thous instead of .44 stated from kia only reason i did is cause it ran perfect no misfire before the tune up and i read a post saying something about wrong gap in manual.its been 3 days so far no misfire.still have the code 452 evap pressure sensor signal low if any one can help.checked and replaced all damaged or broken vac lines tested purge solenoid and the bypass solenoid for resitance and volts as the book says r within specs and the sensor on the fuel tank has voltage.any help would be apreciated thanks for all the help