Error Codes I dont understand-
 

Hey-

Here's Whats up,
We have a 1998 V70 GLT 2.5 fwd Volvo.
Its about 150,000 miles and in nice shape.
A while ago it gave us a P0410 Error and we ended up replacing the Air Pump and A Valve That was on top of the turbo (i think it was like a check valve or something)
so after that it ran good for a bit (2 months maybe?).
Now its giving us 3 error codes and even dying somtimes.
The error codes are the P0410, P0243 and another one that says the system is running lean (i didnt write it down sorry-).
Alot (almost all) of the hoses have been replaced on this car.
Yet its still running really odd. Some times it runs fine other times it Shudders and runds really rough.

Can you help me?
I dont have any ideas and im getting frustrated with it.

Please help