Hi All , my first post after selling G6e turbo and going as old school as my wife would allow . I recently purchased a 98 XR8 manual , it has ran reasonably well but recently has been surging on constant throttle and pinging unless on premium . Now the idle is fluctuating badly between 500 - 1200 rpm and sometimes stalls . Sometimes it runs fine with none of these symptoms . From what I have google doing fault code test won't show anything as it isn't showing an engine light . I have checked many sites and many threads but can't find anyone with all these symptoms at once . The car is stock. Thanks for your input . Brett

Dirty MAF , vacuum leak. PCV leak?