sigley0527

Im new to the site...I've done lots of research on this but still dealing with this frustrating problem.
I own a 2000 4runner Limited 3.4. I'm doing my best to learn about my truck to the point where I'm able to do general maintenance repairs on my own.

It all started a couple weeks ago when my check engine light came on. I went to autozone and put in on the computer. P0171 System to lean Bank 1 and P1135 A/F sensor heater circuit.

From what I researched majority of the time P0171 is due to a dirty MAF sensor or possibly a vaccume leak. I also figured it could be a "side-effect" code to P1135. My buddy is a mechanic and he helped me clean the MAF sensor...we also checked for a vaccume leak and found nothing. We reset the computer and about 3 blocks down the road the light came back on...P0171 and P1135.

Time to replace A/F sensor figuring this would be the fix. I went to Toyota and bought one and replaced it. Reset the light again, I thought I was home free. After 20 miles the light came on again. P1135 is gone but its still showing P0171. I have no exhaust leaks, no vaccume leaks, clean MAF sensor, and new A/F sensor. I just want to know if there is any other route I can exhaust before I replace the MAF sensor...Thanks for the help in advance.

cpizzle42

How did you clean your MAF sensor?

Do you have stock intake? Is the filter clean?

sigley0527

I forgot to mention that my truck runs completely fine with the check engine light on. No idle/acceleration/bogging problems at all.

sigley0527

We cleaned it with electrical cleaner. Yes I have a stock intake...and the filter is pretty much brand new. Replaced in less than 2 months ago.

ToyoTech559

did you spray and clean down the tube of the maf? not just the tip.