rouch idle

[silveradodude]

My buddy has a 1998 tahoe with the 5.7 vortec that runs and great has 58,000 on the clock. recently it has developed a lumpy idle. He has done all the basic tune up things but still has the rough idle. what strikes me funny about this is that 3 of our freinds have the same truck and have the same issue.

 

Is this a common thing with this engine? What should we look for first?

 

I appreciate any help or a push in the right direction

 

thanks