I've had my new Jayco Precept 35UN for two weeks now. Jayco did a nice job adding some really huge bars on it but it was driving where it wanted to go when I brought it home.
The DOT sticker says 90psi front and rear but when I checked tire pressure I found 86 psi with two high quality gauges that agreed. I brought the tire pressure up to 95 psi in all tires and it is a new machine!! I will run it at those pressures but your rig may differ - remember Jayco did some work on the suspension already.
Mine is not driving like a car but is much improved with corrected air pressure in the tires. I would start there and see if you get improvement like I did.