2000 I30 w/2 codes (P0134 and P0171)

[am81696]

Hi all...new forum member but long time lurker. Found numerous resolutions on here in the past for my 2000 I30. But now I have an issue that I haven't seen a fix for. My I30 currently has about 270K miles. The check engine light is on and throwing 2 codes P0134 and P0171. Over the past few years, we've replaced one of the O2 sensors and my husband replaced the MAF sensor just over a year or so ago. When the codes came up, he attempted to clean the MAF to see if that would work. He cleared the codes, but within 30 or so miles, the check engine light was back on. When we had the codes read at Autozone, the slip that prints gives us various reasons for each code. But to just go down the list and start repairing one by one could get expensive. Any ideas what these two codes together could mean? Is it an O2 or the MAF or something else???
Any help is appreciated!

[MTZI30]

Do a google search im pretty sure those are codes for a bad 03 sensor and a lean mixture. You gotta start with the 02 sensor.

[loystock]

P0134 is for Bank 1 Front Heated O2 sensor; P0171 is for Bank 1 Fuel injection problem. Most likely, P0134 was triggered by problems with the fuel injectors. Please see attached link:

http://www.nicoclub.com/FSM/i30/2001/ec.pdf