So my 4Runner has been throwing this code for a while, happened the first time going up hill in the mountains, so there was some strain on the engine when it happened, read the code and cleared it to see if it would stay off, it did for a good while then came on again under strain, and stayed on. I replaced my bank 1 o2 sensor, so that's not the problem, but then I cleaned the MAF sensor and it cleared the code, it was good for about 4 days(luckily I got it inspected in those 4 days) but now its back again! What would make it leave then return like that? The code was just back after it sat undriven for a day and night. Next thing on the list to do is replace the fuel filter, might as well, it prob needs it anyways, thought I think it might have something to do with the intake since cleaning the MAF fixed it for a little?? Im at a loss...

I am aware of this...

P0171

so I know what the code is for, just wondering if anyone had any ideas on my particular situation.

 

I would check the O2 sensors but thats just my two cents, oh yeah the fuel filter is a good idea too.