3.4 Engine help

So, I definitely have a type of vehicle that we favor at my house, just look at my sig.

I have a problem with the 3.4 V6 in the 4Runner. I'm asking here due to the quality of responses I've seen on other thread, and hope I can get some help other than "Hit it with your purse."

A few years ago, it popped a CEL for a bad O2 sensor. Replaced sensor and rode on. The light kept coming on. New sensor, more light. My code reader was one of the cheap eBay ones that connects to your phone with Bluetooth. As long as I left the reader plugged in, the light stayed off. Unplug the dongle, and the light would be back on after a couple of miles with the same P0135 code.

Fast forward a couple of years, and a new phone wouldn't connect to the dongle. Bought a more adult code scanner like the big boy I am. This one I can't leave plugged in because it will drain the battery.

Now, if I drive long enough and don't erase the codes:
the engine will idle rough,
after a reasonable amount of time above idle (pleasant driving, driving Miss Daisy) when I come to a stop, she just dies.
it hesitates, and stumbles trying to accelerate.

Clear the codes, and I have none of those problems. Here are the codes:
P0130 -- O2 Sensor Circuit Bank 1 Sensor 1
P0133 -- O2 Sensor Circuit Slow Response Bank 1 Sensor 1
P0135 -- O2 Sensor Heater Circuit Bank 1 Sensor 1
P0141 -- O2 Sensor Heater Circuit Bank 1 Sensor 2

Eventually, I'll have a couple of misfire codes too.

This is a nearly bone stock T4R Limited from 2000. My wife loves this vehicle. I'm starting to not like it so much because I can't figure this out. I've heard to try replacing the spark plugs. I've heard to try new O2 sensors (my new ones were from Toyota). I've heard to get a new c. converter. I don't have the deep pockets to just throw money at it nor to take it to a shop over and over for them to make me throw money at it.

My concerns are:
What would leaving he dongle plugged in have to do with the codes staying off?
Why would it pop the O2 Sensor code 2 days after putting in a new OEM sensor?
What is causing it to stall?

Any help is appreciated.

 

You say no codes set as long as a scan tool is plugged in correct?
If that's the case you almost certainly have a bad ground as most scan tools jump Pin 4 (Chassis Ground) and Pin 5 (Sensor Ground) of the DLC together when they are plugged in.

My bet is the Brown wire is broken at Ground Point EC

 

You would not believe what I found. The (insert Christmas Vacation rant here) bolt holding the ground strap was loose.

Thank you so much for your help and direction to start looking. You saved me and my wallet one helluva heartache.

 

That would do it

 

Glad it was an easy fix. Those grounds can be quite Finicky !

I just snugged that bolt up one day and the truck would not start.