P0505 Loses idle, 2AZFE 2009

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adamp1027
Posts: 10
Joined: Fri Apr 20, 2018 6:33 pm

P0505 Loses idle, 2AZFE 2009

Post by adamp1027 »

Hello!

We've had a low, rough idle for quite awhile on this car, now at 120k miles.
Did all normal tuneup items, plugs, air filter, cleaned throttle body, idle relearn, new MAF sensor, no change in rough idle.
Replaced throttle body and pcv valve (pcv valve was pretty gunked up). New throttle body is Cardone brand, with the new 3 vacuum port design.
Now I get this weird behavior.

If I clear codes with scan tool, do idle relearn procedure, put in drive, and let idle, idle will settle at 800rpm and sit there indefinitely.
If I move put it in park (or drive it), rev engine, and then back to drive, idle will move to 900, repeat, and now idle is 1000. Each time, the idle at park is also moving up, until it's about 1300-1400. Around here is where p0505 gets thrown.

I've taken it all apart again and checked all vacuum lines, everything looks good.
I only have 2 ideas left, hoping you guys have more.

1. Intake manifold gasket is leaking, and replacing all the other stuff has revealed this problem? When car is idling at 800 like it should be, the short term fuel trim is about .78%, which makes me think there isn't a leak.
2. New throttle body is the problem. The note on the part says that new design is 3 port, and no need to plug the connection into the intake where the 4th vacuum line used to be. I've tried plugging that connection, and it makes no difference. All of the other parts by different brands for this car are also the 3 port design. Could it be that they screwed up, and we do need the 4 port design on this car?

And yes, my gas cap is on.
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