2004 ram 5.7 PO172

[doddgeman]

I have a PO172 engine code.
On my 2004 ram 5.7
It only happens when I pass someone fast
After I turn off truck it resets
Any ideas on what is causing this?
Thanks

 

[aszumilo]

Could be a MAP sensor or the vacuum line.

 

[Ken226]

That code indicates a rich condition on bank 1.

Rich on only one bank is a good indicator of a leaking or stuck injector.

If you have a scan tool or AlphaOBD, command each of the injectors on bank one to open, one at a time, and see if they all respond. If you don't have the equipment/expertise to do that, take them to a shop that does and have them tested.

Also, if you have AlphaOBD, go for a drive with someone else driving and monitor the fuel trim from the passenger seat, while accelerating hard

If the PCM is trying to lean the mixture, but still running rich, that's a good indicator of a faulty injector.

DONT replace them all with cheap aftermarket injectors from eBay/Amazon.


If you wanna try a hail Mary before doing all that, run some fuel injector cleaner through it first. Since your issue is intermittent, the injectors may just need cleaning.