P0171 to P0330 codes

Newbie here!

I am having troubles with my newly purchased Tacoma...

It is a 2000 SR5 3.4L that I picked up about two weeks ago. The PO told me that it was throwing the P0171 (system to lean bank 1) code and that he was going to be replacing the O2 sensor (before the CAT) before selling it to me. I drove it for a couple of days before the CEL came back on for the same code. I found a hole in the air intake hose, which was causing a vacuum leak, which made me believe that it was the cause of the code. I replaced that and drove it for another 2 days and the code came back on. At this point i decided to replace the plugs, wires, and MAF sensor. After replacing all that i took it for a drive and now it is pulling a P0330 code (Knock Sensor 2 Circuit bank 2). Now I am stumped and do not know where to go from here. Any ideas??

 

Anyone??

 

Bump. Figure anything out on this OP ? I have a very similar problem.

 

Unfortunately didn't figure out the cause of the initial problem. Replaced knock sensors and haven't has a CEL since.