po343 is camshaft sensor 1 bad and po171 is bank1 sensor bad, in English po343 cam sensor is mounted on back of engine and hard to get to, the po171 is bank 1 o2 sensor easy to replace.
System to lean (bank 1). There is a good chance you have a vacuum leak under the hood.
P0171, system too lean (bank 1). P0174, system too lean (bank 2). Start with checking for a vacuum leak.
leaking intake gaskets...
PO171 = system adaptive fuel too lean (bank 1) PO174 = system adaptive fuel too lean (bank 2)
system to lean bank one 02 sensor ?
po171--- system to lean (bank # 1)
P0171 System too Lean (Bank 1)
Fuel injection system, fuel trim to lean (bank 1)
Trouble code P0171 Means: System too lean (bank 1)
Code P0171 means System to lean (bank 1)
Check your EGR valve or see if there are any vacuum leaks. Other than that, no special ideas.