who can figure this out for me---I am begging

how fast do you drive? how many miles on it? did you buy it new? socks/struts?
my 08 is perfect on the hywy at 65 mph, 20K miles on it.

 

Try and drive another Prius, RENT one if you must, and see if you feel the same way. If you still feel it's unstable rent a 2nd one. If you 3/3 are unstable then it's likely that the Prius is out of your "specs".

I drive 75 regularly and on an even surface I can lift my hands off of the steering wheel for 4-5 seconds just to test the alignment. It's well within my limits of "tolerable" but it's not perfect. The car feels light on the road but I am used to it. I have 46 psi on my factory tires and they have an extra year (entering their 4th) of life "at least" according to the my mechanic who would make money off of replacing them.

 

Your front alignment measurement seems fine. The steering wheel position is adjustable, by adjusting the tie rod ends. Was the steering angle sensor zero point calibration performed after the wheel alignment was done?

The only potential concern would be with the rear suspension where toe on one side is less than the other. It is still in spec though, as spec is 0.3 degrees total toe, +/- 0.25 degrees. It is possible to adjust this with the use of shims, although a Toyota dealer typically will not do this as the repair manual recommends replacement of rear suspension parts.

What tire pressure are you using? Suggest you try 35/33 psi if you currently are using higher tire pressures.

 

It would have been HELPFUL also if you past in your avatar, what part of Florida you live in. For example, driving into Indio CA has frequent high winds. Same with some of the mountain passes in Montana. That can cause the car to buffet about.

 

maybe it's a "feel" thingy. what did you drive before the prius?

 

I stuck a front shock upper strut bar on my 06 and it helped out the wandering feeling a great bit, but after I replaced the rear stabilizer bar with a trd (Toyota racing development) the car became very stable.
Everyone will give different information about tires but I like the Michelin hydroedge, it evacuates water excellently when needed, true it's an all season and you're in Florida but you do have torrential down pours... when you don't have droughts.
You may have a bad tire doing all the mischief, one broken chord in the sidewall will make for a miserable ride.A strong sidewind effects the Prius in a most precarious way and as you know in Florida the wind can be non-stop and with no hills to block it, it just constantly pushes the car around.

 

I noticed a similar thing when I moved from a VW Jetta TDI. I also drive a Miata MX-5.

Both of these cars exhibit very precise steering and excellent handling, so when I bought the Prius I thought, hell, this thing handles like a mini van in a beam wind. But setting the tire pressures to 38 front and 36 rear seemed to help.

Also, I find that I'm now adapting to the sloppy (relatively) highway handling of this great little money-saver.

 

Determining root cause for a difficult problem
is most efficiently done if you first put some
thought into how to approach the problem.
The key is to create a plan whereby at the end
of the process, you have moved closer at a
minimum to understanding the facts and
even better hit that "ah ha!" moment. The
three approaches people typically use are:

1. Best guess...try something that seems likely
to solve or improve the problem, and hope
it works. Some people call this, "throw it
against the wall and see what sticks."
2. Ask an expert.
3. Process of elimination.

--

For #1 to work, you have to have a reasonably
accurate educated guess as to what the problem
might be, and it helps if there is only one problem
to start with. The advantages of this are that it is
relatively inexpensive to do, takes a fairly low
amount of expertise on your part to implement,
and if you have even a little luck, you might
stumble upon the root cause. The downside is
that it can take a long time, and it can gradually
build up to be quite expensive both in terms of
parts/services you have to buy and your own
time.

In your case, #2 would be to go to a Toyota
dealer, ask them to send a tech out with your
on a ride, reproduce the problem. The tech
should be at least able to tell you if your car
is handling normally. This will probably be
rather expensive, but presumably the expert
will be able to confirm whether you have a true
problem and perhaps even be able to tell you
what the problem is.

Approach #3 is basically a systematic, "divide
and conquer" technique. If you start with the
right set of things to look for, you will invariably
eventually isolate the problem.

If you decide to do #3, definitely the next step
is the suggestion to rent one or two other Prius's
and see if you experience the same handling
problem. (One issue with that is that rental
car companies may have phased over to the
2010 model year; you will be lucky to find your
2008 model, but you might find a 2009 which
probably will suffice). If you can confirm that
it is your Prius that is the problem, what I
would do as the next step is to get a Toyota
tech to drive with you in both yours and the
rental car, thereby demonstrating that your
car does have a mechanical problem. Beyond
that, the next step would be to identify those
car components that affect handling and test
those one by one (personally, I'm not
sufficiently mechanically inclined to be able to
do that).

 

Not sure if this is what you are experiencing but when I first took delivery of my 07 its most irritating thing it did was the constant hunt of the steering. Unlike every other car I have owned you must pay attention to this car's steering. Constant micro correction needed. Can't take your eyes off the road really.

Most cars you can just relax and truck on down the road and hold the steering loosely and not pay a whole lot of attention to it and will roll real nice and straight. Not my 07.

I was very unhappy.

I posted this complaint years ago and many posters just like Patrick here said tire pressure.

They were right. At least for the Goodtear Integritys. Which is really one of the world's shitt*est tire.

My 07 was delivered with 28 lbs in all the Integrity tires. At 28 lbs it was a constant hunt and peck steering.
I pumped it up to 45-43 and the hunt pretty much stopped but the road noise was horrific.

I only have 27K on these tires and really don't want to put new tires on till at least 35K miles so to mitigate the road noise I dropped the pressure back down to 32 and bad hunt and peck came right back.
Mileage suffered too.

So I see you list new tires but I hope to god you didn't buy Integritys again. Please say you didn't????

Because if you did.... all drivability complaints are off the table till you get a set of good tires on the car. Sorry.

Try pumping up to 45-42. It will be loud but will roll mostly straight and get good mileage.Still tiny hunting but better.
I have really good hearing so Noises drive me crazy so I opted for the least amount of annoyance. I'm so used to its driving.

Unlike my Crown Vic which will roll in a straight line for miles and miles.
Good Luck!!

 

I want to second the comment about driving another Prius or two. The steering on the Prius does have a different feel (or lack of feel) from most cars. There is little dead band and tiny hand movements are transfered to the wheels. It took me a while to get used to it.

As pointed out above, your Prius may have a problem, or it could be nothing more than you not liking the feel of the car. Until you test drive another Prius you won't be able to say which it is.

Tom

 

take a gen III for a test drive and let us know what you think. it would be an interesting comparison. i have to think something is wrong with your car, this is not a big complaint around here.

 

I can compare our Prius to our Subaru. The Prius without a doubt has a touchy steering wheel. My adjustment to it came when I learned not to over-correct. Nowadays I don't really prefer the Prius handling on the highway, but it's fine. Well, except on windy days; then I have to fight a bit.

 

I use 44/42 PSI tires. After a month I got used to the squirrelly steering and ever since it feels normal.

 

Your problem has all the signs of an out-of-spec rear alignment. I would take it to the Toyota dealer (if you know a good one) and have them do the alignment. The rear alignment is not adjustable in the usual sense on the Prius, but don't let them try to sell you a new axle beam - they can shim the rear hubs into alignment. And experiment with tire pressures.

 

i'll take your word for it, i havnt noticed for some reason. good luck, i hope you can sort it out!