900 Miles into owning a Z 71 with a 3.0. So far loving it. Fuel mileage is very impressive. The highest at 31 setting the cruise on 65 on the interstate. I am averaging about 28 cruising at 75. I have had a check engine light on various times. I took it to the dealer and they said is sensor out on the emission package. The light seems to come and go as it desires. It has not affected mileage or running . The sensor has been on order for about a week and a half now. The dealer thinks they’ll have it in by next week. I’m not holding the dealer responsible or GMC responsible for the part delay due to the current environment we are in. so far I’m very happy with the purchase.