Hi all. my first post and it's a problem...nice!!

Had an issue with my 2002 A6 2.7t for a bit. Had it go into limp mode recently. Had it plugged in and it came up with the following:

P1459 - Exhaust Gas Temp Sensor 2G 236 Implausable Signal.

P0300 - Random/Multiple Cylinder Misfire
P0301 - Cylinder 1 Misfire
P0303 - Cylinder 3 Misfire
P0304 - Cylinder 4 Misfire

Had the faults cleared as I didn't know how recent they were and the car was fine...for a couple of days. Then it started stuttering and the engine management light came on. Had it plugged in again and it came up with cylinders 1,4 and 5 misfires. I've just changed the plugs and coilpacks and the fault's still there, stuttering real bad and engine management light on. It does now sound like there's a boost leak as I can hear a turbo or both spooling up..not screaming but you can sound the boost alot more?


I had the car checked again yesterday, it's kept with the multiple misfires even with new coilpacks and spark plugs...cylinder 4 being the most common to flash up. The exhaust gas temp sensor 2 had shown as intermittent, short to ground. I also had the car tested for boost leaks and it had non...1.5 bar they pressurised it up to, but it did then show an issue by oil getting past the rings and it being smoky for a bit! The car's got 150k miles on it so is this just a bit tired or is it a bit more serious?