At start up this morning car started to miss at idle and hesitate when accelerating up hill. The hesitating did get better as I continued to drive and the engine became warmer. It has been missing some at idle this week with no visible dip in RPMs but did not hesitate while driving. I do get a random CEL for P0138 but it is on again off again.

Checked code when I got to office and it was a P1138 - Manufacturer fuel air metering.

Any thoughts on where to start? Plugs, Wires, Mass Airflow Sensor? Maybe all of the above.

Thanks,
Mitt

 

foggy and damp this morn?
me too - mine is from a cracked coil pack I have yet to replace

 

It was damp after some heavy rain last night. I am guessing o2 sensors for mine as well. I will take a look at coil pack.

Thanks,

 

do it when its dark out - you may see the actual arc
check your spark plug wires too - if they are old and cracked - could produce same issue
personally - I would reset the codes after getting this sorted then see if you still need a o2