P0172 after fuel injectors.

Ok, the IAC (idle air controller) is located under the throttle body. It is attached with four soft brass screws. There is a gasket that goes between the IAC and the throttle body so you may need a new one before reinstalling. Make sure to dutifully take note of how the coolant and vacuum lines attach. Use the search engine to find out a better write up on such.

IMHO, if you had new 02 sensors your fuel trims would probably register quicker and more accurate than at the moment but don’t think it is your problem.

Nope, the TPS seems to be reading correctly. With the butterfly closed the sensor should read about 9. That is why the value of 8 for your MAF at idle is something to make note of.

Good luck.....
 
I just dealt with a bad TPS. It wouldn't register the idle throttle position correctly and would cause it to stall. Also upon deceleration, the engine speed wouldn't decrease until a few seconds after I let off the gas (sort of like a runaway vehicle). If you don't have symptoms like these then assume the TPS is good.

You're on the right track though. The major sensors that control fuel are MAF, O2 sensors and TPS.
 
So I'm going to see if I can find an IAC seal local on Saturday and clean it out. I watched the Timmy Tool man's video on cleaning it and sounds like my issue. I also need to stop my pick n pull and might just grab a throttle body.
 
Bucket81 said:
So I'm going to see if I can find an IAC seal local on Saturday and clean it out. I watched the Timmy Tool man's video on cleaning it and sounds like my issue. I also need to stop my pick n pull and might just grab a throttle body.
Click to expand...


It’s worth getting one or two spares out of the yard just for the spare factory sensors.


Sent from my iPhone using Tapatalk
 
Well that's gross...

My local dealer ship didn't have the gasket in stock so I got to wail tell Tuesday to put it all back together.
I also found a pretty bad oil leak...
6766d45cee4667089b4d893025ba719f.jpg
 
Try Felpro 61087. I used it on an IAC cleaning on a Tacoma years ago and no problems as of last year.

How dirty was the throttle body?

Grab a MAF as well if you make it back to the junkyard again........
 
If you do plan to replace the o2 sensors, Denso and Genuine Toyota is the way to go. Sometimes Genuine parts can come out cheaper than Denso. I've had my truck since 2014 and both o2 sensors have never been changed (there is no record of replacement).
 
Holy crud Batman! That IAC needs a proper cleaning, or replacing. I don't think it will cure your P0172 but you should get better idle quality. I had to bite the bullet and get a new one recently since my was toast beyond the point of cleaning.
 
gamefreakgc said:
Holy crud Batman! That IAC needs a proper cleaning, or replacing. I don't think it will cure your P0172 but you should get better idle quality. I had to bite the bullet and get a new one recently since my was toast beyond the point of cleaning.
Click to expand...


Most manufactures don’t mount the IAC right under the throttle plate where dirt and debris can collect.


Sent from my iPhone using Tapatalk
 
I am hoping your 4Runner now idles around 700rpms give or take.

I would start with replacing the oxygen sensors. After 20+ years they are bound to be on their last leg. And that is the correct Denso number. Mike replaced his oxygen sensors concerning a PO172 and it fixed it though you don’t have that code anymore:
P0171 - System Too Lean Bank 1

Others have used that specific Denso MAF with success though Amazon says it isn’t a fit...
 
LittleCaesar said:
I am hoping your 4Runner now idles around 700rpms give or take.

I would start with replacing the oxygen sensors. After 20+ years they are bound to be on their last leg. And that is the correct Denso number. Mike replaced his oxygen sensors concerning a PO172 and it fixed it though you don’t have that code anymore:
P0171 - System Too Lean Bank 1

Others have used that specific Denso MAF with success though Amazon says it isn’t a fit...
Click to expand...
No still ideals around 1000 RPM...
 
O2 sensors didn't change anything.... And I cleaned the MAF again and no CEL.

Could it be timing? If it was wouldn't I get a CEL?

edit: I noticed it is affected by temperature. So when its cold it doesn't start breaking up tell it hits a higher RPM.
 
Concerning the TPS, use the live data app gradually increase the throttle up to 3500 or so and make sure there is a linear curve it follows for values.

I hope someone else will post their MAF value at idle, operating temp.

No, not timing.

Original alternator?
 
LittleCaesar said:
Concerning the TPS, use the live data app gradually increase the throttle up to 3500 or so and make sure there is a linear curve it follows for values.

I hope someone else will post their MAF value at idle, operating temp.

No, not timing.

Original alternator?
Click to expand...


I posted my MAF readings in the too lean thread.


Sent from my iPhone using Tapatalk
 
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