Sent my 4Runner in a few weeks back with a p0171. My mechanic said a rodent of sorts chewed through the air filter and got some junk on the MAF. He cleaned the sensor and replaced the filter. Light went off until a few days ago. I filled up with gas, started my drive to work and the CE light goes on. I scanned the codes and again it was a p0171. I checked the filter and she is fine.

So my first question is what the hell could be doing it now? I just passed 125xxx miles. The rig is driving fine though. No noticeable change in driving characteristics.

My second question, I NEED to drive to Philly this weekend. If the it's running lean, can a I make it from upstate NY to Philly (6 hrs.) and play it safe on a lean system, then deal with it later in the week?

Thanks,
Lou

 

Have you replaced the O2's/AFR's? As time goes on these sensors may not throw codes but be going bad. Even without a code they need to be replaced around the 100k mark. That goes for the TPS as well. The O2's are little spendy but the TPS is only like 40$ It might also be possible that the MAF sustained other types of damage......

 

I agree change the oxygen sensors the maf was cleaned already look for a used one and then the egr if you truck has one maybe stuck .

 

X2, Change the oxygen and AF sensors first. I was throwing P0420 codes (Bad CAT's), and I couldn't believe that, so I replaced the sensors, and I then threw the leaning out code like you, and it was my MAF. Replaced those three, and I was still under the price for the replacement cat. And the beast runs 10x better now.

I drove a long time with the codes, and it didn't hurt anything, so you should be ok.

Mark

 

Are you sure that the mechanic cleaned the correct sensor? The MAF has an intake temp sensor that is the first big element you see. Down the two shafts of the MAF are the sensors that would set off a P0171 code. I suggest you remove the MAF and spray it down with the correct electrical parts cleaner before you start throwing parts at it.