My van shakes when driving uphill. I think it mights have something to do with the tires.
It could possibly be tires, but tires are in motion if you are driving. Usually tire issues are motion and speed related. It is possible that the shaking you are feeling is an ignition misfire. Often times things like ignition wires/boots fail under stress like heavy acceleration or going up hill, and act normal in most other cases. I would suggest asking the help of a mechanic, such as one from YourMechanic aid in a proper diagnosis of why your car is shaking.