Seat Ibisa 2002 Failure

I need help with a problem with my Seat Ibiza. It keeps losing acceleration. I've already replaced the fuel pump, ignition coil, spark plugs, and filters. Sometimes it misfires when it's hot, and occasionally when it's cold. I would appreciate your help.

I had a very similar or identical problem with a Fiat Punto. I replaced exactly the same parts as you, and it was still the same. I had the vehicle for about three months, and the problem was the oxygen sensor. Don't ask me why, because I already know that sensor shouldn't cause that fault, and I don't have any further explanation. I replaced it, and everything was fine. There was no check engine light on or anything; it just occurred to me in desperation.

Can you help me find the electrical control diagrams for the Ibiza? I also think it's the oxygen sensor, but I want to know which one to replace, the front or the rear. It's already been scanned and it does show the oxygen sensor, but which one? I really appreciate your comment. You can count on me as a friend, and I'm here to help in any way I can. Thanks