Advice needed please. Went onto a rolling road for the first time on Sunday and got 130bhp. Was a bit peeved as standard 2.0 Vectra is 136 bhp, mines got sebring exhaust and kn57i. Was hoping for 140bhp. Got told that the car is running and picking up ok just having problems letting the gases out.
I was advised to undo the nuts on the cat flange so the exhaust blows and this will help determine if the cat or exhaust is blocked.
Is this true???