When first playing NASCAR Heat 2, you will have the option to choose between Normal and Expert mode. Normal mode is for casual racers who want to get on a track with assists. Expert mode is more true-to-life. The car will be much more sensitive and you cannot get too aggressive without serious consequences.
You can access and adjust these settings by selecting Options from the main menu then select Game Settings and then turning Stability Help On (Normal) or Off (Expert).