@40 MPG at 67??

On my car, the rear toe-in was different from one side to the other. The right rear wheel was toed in excessively. The car seemed ok at slower speeds, but at highway speeds with a crosswind the handling was very strange to say the least. Once this problem was corrected with shims, the handling was much better.

I would have the alignment checked.

 

Yes, fixing the rear alignment made it much more stable in crosswinds.

Before my car was fixed, we went on a road trip from Sac to Portland OR and back. We had crosswinds the whole way and I was constantly correcting the steering. I realized on that trip that it was easier to steer in one direction than in the other, so I had to correct differently for left turns than for right turns.

 

on a side note, are u sure your speedo is calibrated correctly? 50 psi seems like a lot over the standard sidewall tire pressure, you might actually be going faster than 67.

 

That does seem low. The Prius MPG Simulator predicts 49.3 MPG with your conditions. The simulator does not adjust for the Touring model, so knock off a couple MPG for that.

Could there have been more cross wind than you think? I've known my car to get buffeted by winds on the highway, but only winds considerably stronger than that. What exactly was the wind direction relative to the nose of your car? A wind offset by 30-45 degrees actually is worse than 90 degrees or a straight head wind. A 10 MPH wind from 45 degrees would drop you to 43.7 MPH, per the simulator.

Could there have been a net elevation gain from start to finish? Were there any short hills that could have led to the cruise control pushing the engine RPM into inefficiently high ranges?

And as the others suggest, I'd have the alignment and other mechanical components checked. The Touring model especially should be more stable than what you're describing for the conditions you describe.

 

I would recommend having a shop measure the alignment values. My experience suggests that the electronic, power assist steering seems to mask some alignment problems.

Are you anywhere close to Huntsville AL? Your performance suggests something "ain't right."

Bob Wilson

 

I also suspect an alignment problem. A driver can probably notice an alignment problem if the car is definitely all over the place...pay close attention to your tire wear as well. Only a reputable shop with an alignment 'rack' will be able to tell you accurately if there is a problem or not.

40 mpg is very low...this time of the year I get 51 mpg and up running at speeds between 68 and 70 mph with small hills.

If it is windy, keep your hands on the wheel....the Prius is a small vehicle. Drive safe.

 

FIRST - Drop the PSI, these guys with their 50PSI are a little quackers. Your not going to see any appreciable difference from your previous, safer, pressure.

As for the MPG issue. I have found a quirky thing about the Prius, the entire tanks average MPG can be determined, relatively accurately, from the first half an hour of driving after a fill-up.

Here's what I mean, If I drive in stop and go traffic for the first half hour and get an average MPG of about 48-50 (high for me), no matter what driving I do for the rest of the tank I can almost be assured at least a 44 MPG average for the tank. (Again high for me my lifetime average is 40.5 over 146,000 miles).

However, if in the first half hour I do a lot of freeway driving or mountains and get an average MPG of 39-40, there is almost NOTHING I can do to get that average up to 44 MPG. Weird

40 MPG may be a little low for the driving you describe, but only by 2 MPG, from my experience.

 

I had the same exact thing happen with my dealer. It really pissed me off at the time.

So I took it to an independent shop (a GY tire store) and got a free alignment check (they were running a special). Then armed with the data, I took it back to the dealer.

If you want to read my saga, complete with alignment printout(s), check out this thread:

http://priuschat.com/forums/care-ma...3-2007-model-alignment-issues.html#post440934

 

Since that time I learned that there is at least one company who now makes aftermarket shims for the Prius:

SPC Application Search - Product

I learned that in this thread:http://priuschat.com/forums/prius-m...v4-tire-general-impressions-3.html#post590097

First thing is to get an honest reading of your alignment and see if that is the problem.

Good luck.

 

I'm not sure what's going on with my touring edition prius recently either... I've tracked every tank of gas since I purchased in May of 07. My average has been 43mpg overall and I range from 42 - 45 per tank most of the time ... The last two tanks have both been under 40 (with this one currently at 36mpg). Nothing has changed with my driving and I assumed the first tank was either bad gas, high ethanol content, or something of that nature... bought my 2nd tank from another station and it's getting worse mileage this time around.

I wonder if it's the fuel additives for the summer mix. I'm in Texas in the Dallas area ... anyone else noticing something like this?

 

JimboK, can you still download the simulator?

Thanks

 

something is definately wrong. I've been running 50 PSI front 48 Rear the last month and my wife drives it 3 times a week to school 45 miles each way all interstate. so she close to 300 miles a week the last 2 months and I never have gotten the car back with less then 51 MPG on it. She is a very aggressive driver and also goes about 10 MPH over the speed limit wherever she is which means most of this drive she goes about 75 MPH. She pays no attention to the MFD because she does not have a clue on understanding it. In fact she changes the setting to leave it displaying the radio stations.

 

No. Unfortunately, the developer thinks the registration code got hacked -- he got hundreds of downloads a while back and zero purchases. So he took the download links down until he had time to rework it.