[QUAD-L] Chair Tipping?

[Greg]

 I just got my new chair back from the shop. I have hardly used it. There are 2 worries I have. One is when I start fast, it lifts the front wheels off the ground. Fun when expecting it. I know that can be adjusted with the computer. But the other is when I stop fast, it seems to want to tip forward. I can't tell what happens, it it feels like the back wheels lift up. It might be just the motor area, but not sure. It's a Invacare TDX3. Anyone else have this trouble? Greg