so could use a little help here. My 2009 still throwing code 175. Had it to chev dealer, on scanner for about 2 hrs, everything is good at driving conditions but it stumbles when idling, no obvious issues. Suggested I run cleaners thru it to clean injectors so I did but still stumbles at idle. It is not the MAF or an oxygen sensor as those have been replaced in last year or so. Need to figure this out before my trip to states as it did go into limp mode one time last year, which means 20kph til you clear code.