CEL CODE P0171

For shitz and giggles can you check pressure in fuel rails. How you feel about checking fuel injectors?

 

Yeah, I think I am going to have to take it to the local shop, I have run out of options. Thanks all for your help. If I get this thing fixed I will post what the problem was.

 

If your talking O2 sensors, I installed Bosch.

 

I know you don't want to spend the money if you don't have to but I would replace the mass air flow sensor. Like a previous poster said it may just be shot and time for a replacement. That code (p0171) is typical when the mass air flow sensor is bad.

 

I am a toyota certified master tech and have seen this problem many times especially on the 3.4 v6. It could be a vaccum leak somewhere but most likely it is a dirty or bad mass airflow sensor. Most people will clean the wrong part when trying to clean it. The sphere shaped part that is exposed on the sensor after you remove it is actually just a temp sensor. You have to look inside the sensor past the temp part and you will see a silver wire like thing. This is the part that needs to be cleaned. Use brake clean or mass airflow sensor cleaner. Carb or throttle body cleaner may leave residue on it and cause the same problem. I have seen many trucks with this problem and many times it is because of too much oil on a K&N or similar air filter so if you have one be careful not to use too much oil. Hope this helps!

 

if cleaning it doesnt work you can spray the intake with throttle body cleaner while running. if it revs up there is a leak where you are spraying it. If you dont find any leaks change the MAF. Sorry to say it but you were really wasting your time and money by changing the other sensors. This is actually a pretty common problem.

 

Looks like I might go and replace the MAS since I cleaned the whole probe when I cleaned it the second time using mass airflow sensor cleaner. Thanks.