Service Engine light is on

[coachbradu]

Hey guys! A couple of questions for those in the know. My wife's Tahoe started running rough and smoking slightly. I took it to the auto parts store and had it scanned it detected multiple misfires and bank one too lean. Well, I changed all the plugs and wires and found 1,3,5, & 7 all (bank one) were covered in smut (carbon). However, changing the plugs did not help. My next step is to change the oxygen sensors. The guy at the auto parts store said it may be a coil pack also. He said that he didn't think it was an O2 sensor because the scanner would show it. What do you guys think?

BTW, its an 02 Tahoe with the 5.3.

Thanks,

Brad

 

[tsench]

start her up and unplug each coil see if there any change if no change replace the coil