not my truck but a friends 02 5.3 pops this code every few months off and on. Its the bank 1 lean code, but what causes that issue? I think he replaced 02's the last time it did this. Any ideas where to start looking and fixing?

thanks in advance! The trucks bone stock also if that matters

 

I did a search after posting this.. I found some info and called him and he said he's replaced the MAF and 02's before. But it didnt help. Also, the truck somewhat stumbles from time to time at idle. Im guessing its a vaccum issue.. but where to look?

intake gasket?


please post any ideas

 

intake gaskets!!!!!

 

exhaust leak