Expert: Von Sudderth - 11/7/2009

Question
QUESTION: When my frontier gets to operating temperature it starts to idle very roughly. This happens in drive to and my truck will shake badly. I'm not getting any codes when i scan it.

ANSWER: Billy,

Check for vacuum leaks and if there are none then check the idle air control valve.  It should probably be replaced due to its age.  These are the most common cause of what you describe on your vehicle.

---------- FOLLOW-UP ----------

QUESTION: Thank you I will try changing the iac valve. I took it to a shop and their scan machine said the o2 and mass air flow sensor was bad. I changed both and my truck still runs bad.

Answer
Billy,

If you have a V6 there are three oxygen sensors.  One on each side and one behind the converter.  Replace all three.  Also, be sure to disconnect the battery for five minutes to clear the codes and resident memory.  And, if you replaced the mass airflow sensor be sure that the hose is connected good on both ends and that the air inlet temperature sensor is connected.