EGR valve cleaning

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Prostar wit 570k
When I bought truck they installed new EGR valve, 45k miles on it now
Than I brought it home and did EGR tune up, there was very light soot insite, sensors replaced.
After 15k have to replace EGR Cooler. Then have alarm DPF cloged , in couple weeks same with DOC. I cleaned them at dealership, they was not look bad, that's
also what I been told by service guy.
5 k miles ago I did regen, but sometimes DPF light shows up for couple seconds and then disappears .
My mileage drops from 6.48 to 5.8-6 mile/gal, afterrteatment history goes up from 2.2-3 to 3-4.2 after EGR leaked. I pull out sensor and it's was covered in soot ( sensor 6 month old)
My guess after EGR Cooler replacement need to check EGR valve and dozer injectior right away they may get clogged and that's why mpg is drops
Will update after checking them