P0171 Code

My check engine light came on so I went to a local part store and code P0171 came up and it said "system too lean" and "bank 1".
I got home and looked up the code in my Haynes and code P0171 is "System Adaptive fuel too lean".
Where do I need to go from here? I am thinking either I need to clean my K&N air filter or could it be a bad O2 sensor?

I have noticed that when I step on the gas there is a pinging sound coming from the engine; to remedy this I went to 89 grade octane and sometimes I have had to put in the 91 grade octane fuel, which has helped.

 

Thanks, I will try that...hopefully that will solve the problem.

 

x2 advanced auto has maf cleaner works great

 

I used CRC MAF Cleaner. I also purchased a new air filter and had the check engine light reset. It has not come back on yet. I spoke with a friend of mine that has been a auto mechanic for 20+ years and he also told me to check for leaks in the vacuum lines before I go and purchase a O2 sensor...
Fingers are crossed, LOL

 

Are you using one of the air filters that you have to soak in oil? To much oil could cause problems.

 

maf and vacuum leaks. there aren't that many things that cause n/a engines to run lean.

i once worked on a taco that had a bad pcv valve which caused a ton of oil to get sucked into the intake and soak the maf.

 

TIS disagrees