[ricair]

I just bought a 2001 silverado 1500 z71, and I don't hear any ticking or knocking. May be the hammer is about to drop, it has 75k on it and runs strong. THere is a slight roughness while in gear and stopped, and I feel a slight hesetation when I accelerate off the stop light (only when I floor it). The dealer replaced the master airflow senser (the "service engine soon" light came on even before I got it home!!!!) any Ideas what is causing this. May be I need premium unleaded in it. I just sold my 92 silverado, and it got sig. better millage with premium unleaded...