Rough Idle after start up
 

Anyone have any good ideas on where to start with two system codes? I have an 03 Sub w/the 5.3l with about 80K on it.
P0171System Too Lean (Bank 1)
P0174System Too Lean (Bank 2)
I am just not sure where to start. Just curious if anyone has any good ideas or clues where i can start wrangling this dragon. It is a Z coded motor (E85 compatible) which I just dumped two or three tanks in on a trip from WI to CA. Since then it has run like crap once I got back to CA. I have dumped some Fuel system cleaner and Octane boost in it, in this last tank, no luck. HELP? I am fairly knowledgeable but this is stumping me on where to start, any help would be great. Thanks,

JrBlaster
03 Sub
03 Bonneville

RE: Rough Idle after start up
 

intake gaskets are leaking,gm sells an updated gasket

RE: Rough Idle after start up
 

Thanks P. I will give that a try first. Thanks for the reply,

JB