Nissan Repair: light : service engine soon, vacuum leak, nissan frontier

Question
HiI have a ligh on my Nissan Frontier 2002. The milege is 167,000. The light is there for almost 2 months. It went off twice for couple hours but came back again. Went ot Auto Zone and they check: major vacuum leak. Check all the lines, hoses - none found. Any sugestions? Thanks,,

Answer
Hi Kris -

Seems like you have either an internal vacuum leak, or intermittent one, possibly when the vehicle is in the cold loop (warm up mode).

Tell me - How is the car running? Does it run rough at any point?
When cold, warmed up, or at idle anytime?

PLease get back to me so we can continue the diagnosis.

Thanks and aloha
calvin