High hc emissions - 2005 Daewoo Matiz

Use Google & study Vehicle Exhaust Emission
You'll be there for weeks,if you even understand it all
Could type in: High HC Exhaust Emissions or vehicle
hydro carbon problems
When a vehicle gets that old your close to mechanical
issues that aren't worth fixing

MAP sensor needs cleaning or is bad ?

Emission test by codes reader? or smog? Any codes?

fist i would like you to post the year make and model of the truck along with the HC ppms and NOX ppm it would be very helpful but high hc and nox can be attributed to a faulty EGR system nox is produced when the combustion chamber temperature gets too high so a small amount of exhaust is cycled back into the air stream to help cool them there are other causes but without looking at the levels its much harder to say

Replace your oxygen sensors.
murf427

hi.
first thing to do is change the air filter. even if it appears clean, the airflow can be blocked enough to affect the petrol air ratios in the engine which will give high HC readings.
changing the spark plugs can give a cleaner spark, and better ignition, with lower HCs. high HCs could also be caused by traces of oil getting through worn piston rings and valve stem seals and burning in the combustion chamber. there are many oil additives that can help stop this and reduce HC levels as well.
hope these suggestions help

High HC counts are due to a rich mixture, too much fuel. How does the truck run normally? To adjust the fuel mixture at the carburetor, make sure the truck is at operating temperature. Turn the idle mixture screw clockwise until the engine starts to lag then turn the screw back just until it runs smooth. Also make sure you have fresh oil as this could cause high HC's as well since fuel gets into the oil and make sure your PCV valve is operating correctly. If you can't get it adjusted correctly, you may have to pay a shop to hook it up to the emissions machine to get the mixture correct, unfortunately.
Hope this helps. Good luck!

Not sure, but did you replace the oxygen sensors. Is your catalytic converter still good?

Check vvt servo motor

1993 DODGE CARAVAN 3.0 HCPPM LIMIT 144 READING 172 NO PPM LIMIT 965 READING 1024