Hello there,

can someone point me in the right direction???

driving the car (02 vrs octavia) when the turbo starts to boost you can here it slow down then start up again and its not until you hit the higher rev range when it acts fine.

also every 14 mile the engine warning light comes on giving my cheap code reader a code of p0141, o2 sensor fault. I've just got the car and it has a k&n filter, forge dump valve and a decat pipe.

is there something I'm missing here?

It will have warning light on as they have 02 sensors either side of cat so it knows it has a decat pipe on and is putting warning light on, you could try a 02 spacer and space second sensor out of exhaust flow,

With decat fitted it allows the turbo to spool up faster and it may be that you can feel, the car maybe overboosting and the engine ecu maybe cutting the boost pressure back to compansate and thats what you might be feeling as its cutting and then boosting again

thanks very much for that advice, i'll try that asap.

Crappy remap at a guess!

If you dont know what your doing when you map these you can get the boost surge!

Take the car to r-tech for a proper remap

Has it always surged like that? If it's mapped (badly), then that could be the problem. Could also be a failing N75 valve. Me, and a few others on here have had the same problem and tracked it down to the N75.

Can't see the decat making that much difference TBH, but it's possible.

thanks for the replies guys, so far this weekend after advice and reading other posts i thought i'd take the engine cover off......

on looking it has a standard dump valve with x2 blanking plugs fitted to the intake pipe with a 6mm pipe blanked!!! I changed the k&n filter back to the original airbox as there was a pipe off the bottom of the air box, now it doesn't dump loud any more.???????its just very quiet. its still surging just not as bad.

as for the map i couldn't tell you i'll have owned it for a week tomorrow and the massive file of receipts and there isn't any receipts for a remap.

where about's is R-Tech?

hinkley and worth the trip