the check engine light just came on in my 98 2500 4x4.  it has a 5.9L in it with 143k and when i went and got the code to find out what sensor is bad all the code gave me was that the truck was running lean and that's it.  nothhing on where the problem is.  i'm guessing the o2 sensors are bad but im not sure.  And about a mouth ago it wouldt start because of carbon buildup in the intake manafoild and idle control motor. all they did was clean it out and readjusted everthing.  could that if they missed something have and thing to do with my problem now or is it a different problem.  any help is aperciated, thanks  

It probably is the O2 sensors. For best fuel economy you should change them ever 50,000 miles.  

yea it was  the o2 sensor.  just figured it was a little early for it to go, just replaced them 4 months ago (good thing it had a warranty on it).