Unfortunatly yes, Got an RS Mongoose Exhaust on, Already got my decat here, but because of an after manifold it didnt fit, so going to revert back to a standard manifold, Both Lambdas are brand new, I did have a look in the cat when it was removed the other day, but al lI could see was a honey comb, unless its breaking up on the otherside to where I was looking,

Just really hope I get to the bottom of it soon, as much I like putting my foot down, it would be nice to be able to cruise with looking like a learner driver,

Have had 2 garages look at it, with diagnostics and not come up with anything, Also had the RAC look at it, for all the good they did, told me my lambda was at fault, when it was my MAF that had failed,