P0172 code after replacing all fuel injectors

FIXITIWILL

MEMBER
2000 TOYOTA 4RUNNER
3.4L
V6
2WD
AUTOMATIC
156,000 MILES

Was getting a heat related misfire for about a month and a P0305 code (cylinder five misfire) on and off. It would clear itself then come back. So, went ahead and changed out all six injectors since the intake plenums were both off, and on account of the 156,000 mileage on the factory injectors.
On the first run with the new injectors the P0172 showed up, and persists after fifty miles on the freeway and a code reset.
Do I have a clogged catalytic converter from the dirty running of the misfire? Or is one of the injectors leaking? Also have a longer cranking time to start the engine, cold or hot, that was not there before.

1 Reply

JACOBANDNICKOLAS

MECHANIC
109,755 POSTS

Hi and thanks for using 2CarPros.

Since you did all of this work, there is a good chance it is something simple. The code indicates a rich fuel mixture, so it is not the converter. Check fuel pressure and confirm the regulator is working and connected properly. That is my first guess. It is possible you got a bad injector, but that is unlikely. One last thing, make sure the coolant temperature sensor is connected.

Also, take a look at the picture I attached. It lists the causes for this code to set. Read through them and see if anything there helps.

Let me know your thoughts and questions.

Take care,
Joe

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