Here are my images of some warmed up idle parameters.



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Yes original alternator.
@19963.4lsr5

Thanks for the the photos. I'll record new data and compare.

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Key on engine off is a good way to test the TPS without worrying about over reving the engine.


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Well I tested it with my foot off the peddle it shows 9.4% and goes to 74.5 at WOT. I also looked at the numbers and everything look similar to mine but the RPM Wich is at about 1200 at idle.

Those are good tps numbers for idle and WOT


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Any luck with a fix for this? Just replaced my 300k injectors and the car went from a long term P0171 to immediate P0172!

Maintenance done:
New injectors (aisin)
New Valve cover gaskets
cleaned IAC and throttle body
Couple of new vacuum hoses
Cleaned MAF (the correct way)

New PCV around 5 months ago
New fuel pump 3 years ago
Swapped MAF with a previous no code Runner around 2 years ago

When's the last time the oxygen sensors were replaced?

Both change in 2017, it certainly could be time again. Car had about 230k-240k on the clock when I changed them. Probably wouldn't hurt to change again...

Aisin didn't make injectors for Toyotas, they are all made by DENSO. It's possible you got aftermarket knock offs. How much did you pay for them?

My apologies, just saw this..
You're correct, not Aisin, I just assumed...
$70 for the pack
ENA 2 Hole Fuel Injector 23250-62040
Pack of 6 Compatible with 1999-2004
Toyota 4Runner Tacoma Tundra 3.4L V6
There might have been a bad one in there...

Just because I'm at 300K/mi. and It's only a couple of hundred in parts and good peace of mind, I replaced:
Plugs and wires (recommended NGK and Denso)
I replaced both upstream (A/F) and downstream (O2) sensors with Denso parts from Camelback
New Fuel Pressure Regulator from Camelback
I swapped in a junkyard MAF (same part #) and it threw a P1133 code, swapped back to my original and the P0172 returned
Found my carbon canister had a HUGE crack in it, replaced that with a used on I had. I'll take some datalogs off Torque Pro tomorrow..
And of course I cheaped out on the injectors

$70 is pretty cheap for fuel injectors. You get what you pay for with those so my bet is those are your issue. I'd recommend getting a set from the junkyard and getting them cleaned/tested or just replace with a quality set of rebuilt injectors.

p0172 rich Bank one, on the passenger side. Take out the spark plugs and see if they have black build up or soot? Will give you an idea on the injectors dumping fuel. Also visually check your exhaust to see if there are any cracks for exhaust leak.

The code says bank 1, but that's because we only have 1 bank of oxygen sensors. It doesn't mean it is coming from a specific bank of the engine.

o
bank one is easier to get to for checking if the injectors are functioning properly.
Bank 1 = Cylinders 1,3,5 and Bank 2 = Cylinders 2,4,6 on a V6.
edit: bank 1 sensor 1 upstream o2 sensor, bank 1 sensor 2 downstream.

Just wanted to make sure people knew that the code does not know the difference between which bank of the engine is running rich or lean.