CODES P0171 and P0106

[Maximus1]

Ok a little history
2004 Tahoe L59 5.3L Flex fuel
Performance cam advertised duration 267/276 lift .525/.525
Performance mass air flow
Headers
Custom tune HP tuners
Scorpion 1/7 roller rockers
BBK 80mm throttle body
K&N cai
MSD coils

Today I drove my truck and everytime I would come to a stop the engine would surge slightly then it would almost die and sometimes it will die. Codes are P0171 system too lean and P0106 absolute manifold pressure out of range I'm really at a loss other than maybe the purge valve or possibly the fuel pressure regulator or map sensor? Before I start throwing parts at it I would like to know your opinion. It seems like everything is more expensive because it's a Flex fuel. I.E. the fuel pressure regulator is $100. Normal engine is half that. Thanks for your help

 

[Maximus1]

Ok so I started off with replacing the simple cheapest thing which is the fuel filter ($10). I cleared the engine codes and replaced the fuel filter. Before I installed the new one I blew through it and it was super easy to blow through. After getting the old filter off I tried to blow through it to see if it was clogged and I could barely get any air through it at all. I let it dry out and still severely clogged. This just goes to show that sometimes what looks to be a complex and expensive problem can actually be very simple and cheap to repair. It's been at least 3 years since I last replaced it so it was due for a change. If you decide to replace yourself make sure you have a fuel line removal tool. Mine was a 3/8. Also my tool was too wide to fit between the filter and the fuel line clamp housing. So I removed the line from the E-85 pump/sensor and pulled the filter still attached to the line out. Then I cut off the filter at the base of the filter. This allowed me to use my tool and pull the other end of the filter out with needle nose pliers. Then installed the opposite way I removed it. Thanks I hope maybe this might help someone else having the same issue.