I have just purchased a golf 1.8t gti. I have noticed that when driving it around for the first 20 mins of car running it drives fine and then goes into limp mode and won't boost past 5 psi. The guy I brought it off has just fitted a n249 delete and a 3" turbo back decat exhaust. Could either of these cause it as there are 2 fault codes coming up for the 2nd lambda sensor.
