I had the same problem in our montana van... along with many others! I took a look at the front seat bolts and concluded that I could put 1/2" or so of washers under the front mounts to angle the seat cushion back. I worked wonders for me. I haven't looked at our sienna yet. It belongs to the wife and I haven't heard any complaintsMPower M5 said:Funny, I'm 5'7" and my wife who drives the Sienna 98% of the time is about 5'6" and we both find that the drivers seat is quite adequate but the darn passenger seat seems to be angled too high at the back of the bottom cushion making you feel like you're going to slide out of it. The passenger seat for some reason is a manual adjust on our XLE.
Is there some way to modify the buttom cushion angle so it is lower towards the back of the seat?
I wish it had seats like in my car which are 16 way adjustable including adjustable thigh bolsters which some of you taller folks could use in the Sienna.