Just listen to the engine. Do it upon a cold start so if the carb cleaner hits the exhaust pipes it won't combust. Start it up and open the engine bay. Just listen for the engine tone to smooth out and fan to slow down. Then just spray on every vacuum hose end as well as the cracks in the the intake 'accordion' pipe. You'll know if you get it, the engine will either rev up or down quickly as soon as the carb cleaner hits the leak and then return to normal. Then replace the offending part. Any vacuum hose can be matched by an auto parts store but the intake may not be carried by them.

Jakeepoo3 has a 2010 4Runner which is a 5th gen. There may be a key sequence for him, but that would not apply to 3rd gen vehicles.

You're right about the generation difference. I didn't clarify. It took me a whole day browsing through the internet to find it after trying all the other methods. There's a video on YouTube that describes the procedure. I can't remember how I found it. The guy was in a Toyota car. He said that it would work on most Toyota vehicles. I didn't think it would work but I had already tried all the other stuff so I did it. It worked! Remember when you do get the relearning process started to let the truck idle for like ten minutes with all your accessories off. Then go through every gear in 2wd, 4wd, and 4lo and let idle for a few minutes. I drive mine like a maniac and give her hell for a hundred miles or so to learn my style. Crazy computers. Good luck!

Actually I found it. Here's the link. Hope this helps you get running properly!

How to reset idle on ANY Toyota car! - YouTube

It is for a 5th Gen. There's very few key sequences for our 3rd Gens and only for late year production vehicles. Too much thinking power for our archaic ECUs

Did you watch the video on the link??

I replace the MAF o-ring after a few cleanings as insurance, or if it looks jacked up. Dunno if an old one would cause a vac leak but the part # 90099-14141

Quick update guys,

Went to a mechanic to get it smoke tested for vacuum leaks and we were not able to find any.

My Denso MAF Sensor arrived and I replaced it and reset the ECU. I took it for about a 30 mile drive mostly freeway to recreate the high RPM acceleration scenario which triggered the P0171 code. I had my OBD Scanner feeding live data and it looks promising. Short and long term fuel trims never exceeded +5.5% even at 2500+ RPM accelerating on to the freeway. Engine feels much more responsive at acceleration at higher speeds as well. MAF reads around a nice 3.43 g/s at idle.

I hope this was the fix and I am out of the woods. I will check in for another update after 100-150 miles or so! Wish me luck guys and thanks for being an amazing and supportive community!

Do you have the part number for the sensor and what year is your rig?