The famous Prius engine stumble at low speeds

Hello Prius peeps. I have a 2013 Pruis persona with 112,000 miles on the clock. No oil burn or coolant loss. I have owned it since new. Plugs changed out at 85,000 E.G.R cooler valve and tube clean at 85,000. Intake removed and cleaned at 85,000 miles along with transaxle fluid.Oil separator installed at the same time all of this work done 1 year ago. I have done leak down test and she passed also camera in each cylinder no coolant fuel pressure right on the money and Tech stream has logged no faults . What the probably is she hesitate at low R.P.M after running for about 12 to 15 mins I am assuming that's after it go closed to a closed loop after warm up. I have ran fuel injector cleaner no improvement . I am leaning toward egr valve but before spending 200 dollars thought I would ask the smartest people I know here on Prius Chat. Thanks for reading this long post

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Yes sorry forgot to mention that was also done when intake was taken off and clean around a year ago

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Catch can around teaspoon empty it ever 6500 miles when I change oil and filter. Map sensor has been cleaned . Fuel pressure checked right on the money

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Fuel trim is with in tolerance . Driving is 90 percent expressway driving. ASE master certified. Going to pull intake and egr system today and take a peak. Have a new set of plugs I will denso plugs with the original heat range. One that are in now are the new plugs with the hotter heat range as per Toyota update. I will report back what I find . Thank for all the suggestions has this has been a brain tickler

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Cooler and egr ,intake was cleaned again today . Only been doing hesitation for a bit over 3 weeks



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Engine all back together hesitation is gone. Only new parts went back to old heat range plugs and egr cleaned and cooler cleaned nothing that was all that plugged up also new intake manifold. Cleaned throttle plate and map sensor . Went for 30 mile ride in stop and go traffic seems to be all good thanks for other suggestions that way I love this place


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Mystery is not the word. On other post should have been intake gasket not intake . I was just shocked that it never logged any codes. Maybe the new plugs that Toyota has suggested with the hotter heat range just didn't work out. Just happy it is running good again

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