I live in a mountain area, many steep hills. When driving down a steep windy road (speed under 30 MPH) I use the exhaust brake so I don't have to ride my brakes. However, the exhaust brake keeps going off and on. Worse yet the engine throttles up increasing speed. I have to then press my brake peddle to slow the truck down. Once I release the brake the truck repeats the same process of speeding up. If I turn off the exhaust brake the issue goes away but then I need to ride the brake. If I am on a steep straight road going over 40 MPH the exhaust brake works like it is supposed to. Another issue of safety is when approaching a stop the engine RPM will not drop below 1200 RPM allowing the truck to slow down unless I push the brake harder then normal. This also happens when driving in a parking lot. The engine will stay at high idle moving the truck to fact in a parking lot situation. These issues are very consistent not just one in a while. I have had the truck into FORD and they say the computer checks out OK. I showed Ford the high idle issue in their own parking lot. They just tell me they can't find the problem. I am not confident that Ford will fix this very unsafe problem. I have now found another person with a 2021 F250 with the same issues. She said Ford will not help her either. I have checked on a few internet forums and see that other have reported the same issues. This is a serious safety issue and need to be addressed. I need to e

- Orofino, ID, USA