GM, in an effort to make their cars slightly more eco friendly, added a feature that puts your car in 4th gear when cruising along in 1st under certain conditions. This is apparently despised by many owners. I is despised so much, that you can buy a commercial product to disable it. That product costs between $20 and $40. Jalopnik has posted a simple solution to disable this feature for under $7 .  All you need is a replacement plug and a resistor. It’s really pretty simple.