Guys
I have a 2004 double cab Z71 5300 engine 14,xxx miles. It has a surging with gentle acceleration when it is cold. It generally emits a nasty odor, not sulphur but a hard to describe odor that is noticed when it is at idle regardless of warm or cold. Mileage is 14 to 15 on two lane highways in the country. It has set no codes and Chevy says it is fine by their machine. Great rig but the surge, smell and mileage no better than my 90 with 197,xxx miles is disturbing. Any ideas?