Help!! after changing the exhaust gas temp sensor on my 2000 s4 the car was flying ( at last) with the remap doing the job and providing a great wallop of power at 2500prm onwards it was a revelation and felt proper fast in all gears. However now 5 days later if appears to have gone softer its pulling quite well but that wallop of power has definatly tapered off and feels flatter by comparison especially in 3rd gear onwards. Any ideas???? I was wondering if it was the standard dump valves are on the way out seeing as its been chipped. No fault codes showing and it seems to run ok but its definatly lost some wallop.