Hello again - I removed the EGR valve (exceptionally for the astra it was on top), cleaned it from carbon deposits, but unfortunately it did not do anything. I went to an electrician and he clearly found that the valve was damaged (valve made in japan, non-regenerative). The new valve costs PLN 780. I have a question about the valve - if the valve is closed, the exhaust gases go directly to the exhaust or vice versa. According to the electrician, my valve is permanently closed, which means that all the exhaust gases go to the muffler and it should be ok, but it's not ok because the engine has no power and still burns too much - please let me know.
