P0171 OBD II trouble code question and help

My truck has been running like crap for some time now with no check engine light. Couple months ago it came on for about 3 hours and shut off but truck still lags. When i give it gas there is no pep in the motor, it goes but you just cant feel it, you have to give it more throttle to get the same sense. I changed my MAF sensor but nothing changed and weird part is some days it runs normal but 98% of the time it lags. Any ideas fellas...oh and happy thanksgiving everyone. New to tacomaworld but long time member to toyotanation

 

How many miles on the engines? The p0171 code is saying the engine is running too lean. I would pull the oxygen sensors out and bench test them make sure they aren't faulty. Remember the O2 sensors have everything to do with engine performance.
Hope this helps

 

intake leak somewhere...

 

vaccum leak most likelly. Check around the air box have seen people change air filters many times and not get the box sealed back tight when they close it other than that check all hoses and around the intake