Right where do i begin lol i bought my 02 vrs in sept and it was blowing so took it for repair it had no cat at the time so fixed the blow and found the rear lambda sensor was not in the exhaust so had it bossed in then warning light came on had bank sensor on the obd finally got it sorted touch wood new sensor from bosch and a high flow sports cat and now the car doesnt seem as powerful is this normal? If so can i sort it out? Surely putting a sports cat on it wouldnt of slowed it down this much any help would be highly appreciated or if anyone with the no how in leicester would like to contact me id really appreciate it i love my car and just want her to stop being poorly ????

a cat could slow it down and if its been mapped without a cat that could also be the problem

Now, I have bumped this, and moved it Skoda octavia 1 forum, rather than "technical guides" in the hope it can be resolved.

And a word of advice for the OP - calling someone geek and goon when someone is trying to help is not the best move in the world!

Well if it had no cat and no sensor, without any warning lights, then it had clearly been remapped for use that way.

With what you've done, it will require another remap to get the best from it. Probably should have fixed the blowing, and left it at that, provided it passed MOT's.

Have you changed the downpipe as well or just put sportscat into standard pipe? The downpipe is restrictive on these cars, and the cat will slow the exhaust flow a little but not enough that you would notice. When I bought my VRS there was no Cat on it so put a Miltek downpipe and sportcat on and didn't really notice that much difference in performance.