Surging/Missing

Help!

I inherited a 2000 Prerunner V6 from my brother when he moved on to his next car and am having some issues with it.

After doing the timing belt, waterpump, and seafoming the engine, I got the following codes.

P0125
P0171
P1130

These pointed to a bad O2 sensor, so I swapped it out with what I told was the correct Denso sensor by Rock Auto. PN234-4162 The pin outs on the connector were the same as the dead sensor, but the connector's locator tabs were a little off which required a little filing to make fit.

The MAF sensor was also replaced at the same time for good measure.


I am now getting a pretty bad miss at idle that clears up when the engine is revved. Under light load the truck will sometimes miss and stumble, which can also be cleared by heavy application of throttle.

I'm also getting a surge feeling under slight load once the truck is fully warm.

The kicker is after replacing the O2 and MAF and clearing the codes, the CEL light is off, and there are no DTCs or pending codes.

Help! I have no idea what to try next.

 

Are you positive that you didn't mess up the timing when replacing the timing belt?

If it's not that, it sounds like an ignition-system related problem.

 

I'm positive. I should have clarified, the truck ran fine after the timing belt job but before the Seafoaming.

I may have figured it out after looking at the connector shapes for the o2 sensor. It seems this truck may have the California emissions system, and I mistakenly ordered the sensor for the Federal system. Would this cause the issues I'm having?

 

How so?



P0125


Insufficient Coolant Temp. for

Closed Loop Fuel Control


P0171

System too Lean (Fuel Trim)


P1130

A/F Sensor Circuit Range/Performance

Malfunction (Bank 1 Sensor





While P0125 is for the coolant temperature sensor, The fixes for mostly relate to the intake/exhaust system.:

Open or short in A/F sensor (bank 1 sensor 1) circuitA/F sensor (bank 1 sensor 1)

Air induction system

Fuel pressure

Injector

Gas leakage of exhaust system

ECM

 

Your the one using all caps

 

I'm referencing the factory service manual, which has a different explantion (posted above) for P0125 and P0171 than the generic OBD P-codes.

The yotatech thread all discusses the o2 sensor, sorry, the A/F ratio monitor.

Huh?

 

the first and last code are for the front o2 sensor. i unplugged mine to test the cat and i got the same codes but i never got the middle code when i pulled mine.

 

Thank you. I'm 99% sure I have the wrong sensor since the part number I was sent is for the Fed equipped truck, and after further inspection, this is definitely a CA model.

 

The Toyota systems are different. A p0125 in a Toyota does not necessarily mean an issue with the ECT like it does on other manufacturers. The P0125 actually, according to Toyota, leads towards the O2 sensor. Strange I know, but true.