Mass Air Flow Sensor

[KNou]

I have a 1999 4runner and I have codes P0171, P1130, and P0125. Based on research, it appears that these codes could be the result of the MAF sensor gone bad. I cleaned it out about 6 months ago and my truck ran well but now it's starting to lag again plus it failed CA's smog test.

I'm thinking that I might just replace the MAF with a new one to see if it will fix all the codes. My questions follow....

Do you think replacing the MAF will fix the rest of the problems?

Can I buy the MAF from a shop like Autozone, Kragen etc or do you guys recommend buying it from the dealership?

Thanks in advance for your help.

 

[004Gunner]

Leave the MAF alone for now. You need to replace the A/F ratio sensor first. It can cause all of the codes that you have now. I paid $160-$165 for my A/F ratio sensor from an online Toyota dealer.

 

[jsmarine]

x2 on the A/F Sensor, also check amazon.com, but be sure to go with Denso, which is OEM for Toyota. When it comes to sensors go with OEM. Check here for part numbers, pricing is a little high, but good source for correct part numbers: Underdog Racing Development

 

[notrayray]

List of OBDII codes and probable causes.

Google docs Toyota 5VZ OBDII

 

[410toy]

if you do have to replace the MFA get the supra one it is will let more air in with less restriction also plugs right in to the 4runners set up.

 

[KNou]

Thank you all for your help. I guess I'll go forward with replacing the A/F ratio sensor for now and see if that fixes the problem.

Do you guys know where the A/F ratio sensor is located and if it's fairly easy to do? With directions, I'm competent I can replace it myself.

I just spoke with Toyota and they said I have 2 o2 sensors. Rear and Front. Do you know which one I need to replace?

Thanks for your help!

 

[brian2sun]

Go to sparkplugs.com and type in your specs since we don't know enough info about yours except it's a '99 4runner. 2wd or 4wd, 4cyl or V6, early or late '99 all make a difference. The front sensor is the one that affects engine performance, the rear one's just there to monitor the cat.

 

[004Gunner]

Thank you all for your help. I guess I'll go forward with replacing the A/F ratio sensor for now and see if that fixes the problem.

Do you guys know where the A/F ratio sensor is located and if it's fairly easy to do? With directions, I'm competent I can replace it myself.

I just spoke with Toyota and they said I have 2 o2 sensors. Rear and Front. Do you know which one I need to replace?

Thanks for your help!

This is a good walk through: click. There may be slight variations depending on federal or california emissions. You will almost definitely need a penetrating oil spray and replacement nuts for the sensor. Good Luck!

 

[sonnydays]

x2 on the A/F Sensor, also check amazon.com, but be sure to go with Denso, which is OEM for Toyota. When it comes to sensors go with OEM. Check here for part numbers, pricing is a little high, but good source for correct part numbers: Underdog Racing Development

Always replace the failed part with the same brand part OEM etc that caused the problem. That way if it happens again you can narrow it down to a specific brand part OEM etc.

Sorry..i couldnt resist.:thanks: