[Wjohnson35]

So I have a 2019 Toyota Corolla Le and originally the temp dropped 12/23/22 and I had p0171 come up and I had both oxygen sensors replaced then same code plus all 4 cylinder misfire so I changed all spark plugs coil packs and air filter. Then p0171 came back checked maf it was good. Now p0171 plus p0441&p0455 just came up as well. It feels like it wants to cut off when I stop but no problem when I accelerate. When sitting idle the rpm’s jump around between 0 and 1. I’m in desperate need of help since I have already spent 600+ on fixing things that wasn’t the problem. Please help!

 

[cj1]

P0441 incorrect purge flow could be setting the PO171.
Verify evap purge valve working normally.
DIY or shop assistance?

 

[petergray8]

You can either throw a purge valve at it (most likely cause of your issue IMO), or get it properly diagnosed. If you have a scanner that can do it, monitor fuel tank vacuum while forcing the purge closed (or just unplug it if you don't have bi-directional control). If it increases then the purge valve is leaking and needs replacing.

 

[Wjohnson35]

So I did take it to the shop again they said purge valve so I changed it myself it solved all the codes went away but then I went around 500 more miles and cel came on with code p0420 and it comes on and off randomly the car isn’t running bad. Any advice on what this could be?

 

[Wjohnson35]

P0441 incorrect purge flow could be setting the PO171.
Verify evap purge valve working normally.
DIY or shop assistance?

Thank you

 

[Wjohnson35]

You can either throw a purge valve at it (most likely cause of your issue IMO), or get it properly diagnosed. If you have a scanner that can do it, monitor fuel tank vacuum while forcing the purge closed (or just unplug it if you don't have bi-directional control). If it increases then the purge valve is leaking and needs replacing.

Thank you

 

[75aces]

Check for exhaust leaks before the cat. The doughnut gasket is not sealing. Could be the exhaust manifold gasket.

 

[cj1]

So I did take it to the shop again they said purge valve so I changed it myself it solved all the codes went away but then I went around 500 more miles and cel came on with code p0420 and it comes on and off randomly the car isn’t running bad. Any advice on what this could be?

P0420 is a cat efficiency code so shouldn't effect how engine runs.
Wouldn't think that the cat itself on a 2019 Corolla is faulty maybe the O2 sensors/plugs/coils that you had replaced aren't OEM? In addition exhaust leaks can be a problem.

Can you record and post the engine data(RPM/ECT/IAT/MAF/A/F/O2/LTST fuel trims?
Looking to see if engine running normal at idle and at higher RPM under load.