Astra 1.8 problem

Another question regarding the obstruction: how can I tell if it's clogged? What kind of test is done? Regards

The catalytic converter has a mesh or honeycomb-like structure inside that, over time, begins to detach and eventually obstruct the exhaust flow. The same thing often happens with the muffler.
I recommend taking your car to a muffler specialist so they can check its condition.
It's not a difficult job, but it does require certain tools.
You'll probably notice a very slight flow of exhaust gases if you put your hand near the muffler outlet, and even if you accelerate.

The best test you can do is to remove the oxygen sensor, which is located directly on the exhaust manifold. Once you've removed the sensor, start your car. If everything works—that is, if it responds to acceleration—then the catalytic converter is clogged, since the exhaust gases will escape through the sensor's opening.

Okay, thank you. I hope that test works. Thanks, I'll do it tomorrow morning and hopefully it will fix it. Regards

Oh, sorry, it's the one in front of the engine, right? Because there's one behind it, which one is it? It's the one in front, right? Greetings