high/low idle and error code PO125 1st gen Tacoma

Since about the end of last week, my 98 v6 auto 4wd Tacoma has been idling wierd. It will either idle too high, or it will idle too low, sometimes low enough that it will stall. The check engine light just come on today though and I had it scanned at Advanced Auto and they told me what coes it was throwing.

Here is what the person at Advanced give me:

PO 125 - Clsd Loop Fuel, Ctrl Insuff, Coolant Temp

PO 130 - O2 sensor Circuit, Malt Bank 1 Sens 2

PO 133 - O2 Sensor CKT, Slow response, Bank 1 sens 1

The truck runs fine while driving it. I have to set it in nuetral when slowing down because it still wants to drive forward when trying to brake. Sometimes it will idle high enough for me to cruise around 35 mph w/o touching the gas if I'm already moving.

I've checked all the vacuum hoses, and all the sensors under the hood to make sure that every thing is connected like they are supposed to be and I can't see anything wrong visually. I think it is some sensor going bad though.

The truck has a TRD drop in air filter, Magnaflow Cat Convertor, and a glasspack muffler. I know that the high flow cat could be throwing the O2 sensor codes but not completely sure about that.

Did I mention that they truck right now currently has over 351K miles on it. If someone could tell me what all this means with the different codes and how to remedy it, I would greatly appreciate it.

 

Is there a sensor going bad that might need replacing? Has anyone had a problem like this before?

I noticed that it wasn't doing it this morning, but this afternoon, it was doing it. Maybe the heat makes it worse?

Please need some help with this.

Thanks.

 

bump...

 

Issue is still not resolved. Please, has anyone gone through this before that can shed some light on my situation. Thanks.

 

I never had that but....
Did you try cleaning MAF and throttle body? Check air tube between MAF and throttle for cracks. You going have to remove it for cleaning anyway so good time to check.
With that much mileage I would get new gasket under the throttle body.
Replace temp sensor just in case. They like $25 and do go bad after a lot of miles (my went bad on LC and had irregular idle too)

 

Hey guys I'm new to the forum and have been having trouble with my '00 3.4l. Shes idling at 2000 rpm and ive changed the iacv (idle air control valve), coil # 3 because it was giving me a P0303, missfire. also i just changed the ECT. Can anyone give me any other ideas as to why it is still idling so high? Thanks.

 

This is where reading sensor data is key in finding the problem. You can read the voltages with a multimeter on the sensor, but will need a schematic to know which wire is which. 3 wire is usually power, ground, signal. 4 wire is usually power, ground, signal, return. The return is a indicator for the ECU to see if the sensor is bad.
You are just guessing without finding a physical cause, ie, broken line, gunk holding the throttle open. Get some diagnostic tools. You'll save money in the long run by not replacing good parts and learn a trade in the process.

Codes are symptoms which give you a place to start looking. Code does not always equal replacing the part the code is pointing to. It can point to another problem. Ie, misfire code because engine is idling too low since temp sensor reads hot and the engine is not.

 

Hey guys I’m new to this forum and need some advice. I have a 2001 2.4L and I just replaced the downstream 02 sensor PO141. It’s currently reading (PO125, P1130, PO171) I got a new air filter old one was bad, also cleaned the MAF sensor. Check engine light went off for 10 miles and came back on. Please how do I fix this