[Scarlet]

Thanks you have all said the same as i was originally thinking, there is no cat on the car its just a straight through exhaust (2.5" if i remember correctly?) .
Got a funny feeling it has something to do with a sensor somewhere just a case of going through everything till i find it, was going to changed plugs, leads, cap etc anyhow.

When i got the exhaust done i thought if its straight through it would help get the gasses out quicker and the guy who done it checked it would be fine before making it up.

Sometimes its a rocket other times it holds back!