I have a problem that when you operate the lift all the way down and press hard that the engine will start to die. To me i think that a relief port valve could be the problem. The issue also occurs when driving forward fast and the same in reverse. The tilt and the Aux have no issues. The lift go's up and down just fine other than when you get to the end of the stroke. Hydraulics are operating ok , no air, leaks or whining from the motors or pump. Need help!!