Weird MPG

[exces6]

I've been noticing some weird MPG readings in my Prius and my MPG has been really low (38.6). When I accelerate, not too fast, I still get 9-15 MPG readings that I don't remember getting before. Also, sometimes when I am coasting, the MPG doesn't go to 99.9 all the time, somtimes i get 70-90. This is weird because it didn't use to do this. I'm doing less freeway driving now, but the only time i see even relatively good MPG is when I get up to speed, and even then they aren't as high as usual.

Anyone know what might be going on?

Thanks.

[rick57]

Hhmmm? Haven't heard from any of my customers on this. Hope its not a big problem and I will be keeping up on this thread to see what others say.

[mikepaul]

<div class='quotetop'>QUOTE(exces6\";p=\"68915)</div>

I've been noticing some weird MPG readings in my Prius and my MPG has been really low (38.6). When I accelerate, not too fast, I still get 9-15 MPG readings that I don't remember getting before. [/b]

"Bad gas" sometimes does that to me. Less energy in it, somehow...

Also, sometimes when I am coasting, the MPG doesn't go to 99.9 all the time, somtimes i get 70-90.

Engine may not be warm enough, if the outside temp is cold enough.

Some days when I finish the 15-20 minute drive to work, I can cruise at 25MPH in stealth through the parking lot, and sometimes I can't...

[LeVautRien]

I've never seen coasting not hit 99.9, I must say. I know bad gas can also mess up the fuel sensor, as it happened to my parents a few months ago. I think it was a high sulfur content that screwed things up, so the gas wouldn't simply have to perform worse. Just a possibility, however.

[Kyle Pehrson]

1st Did you have to have the ecu reprogramed for a P3190 ect.

2nd Also I only use Chevron Gas 88 or higher. Thats just me you can take it for what worth.

3rd It is normal to see that go from 5mpg to 99 Remember it is not lateral it is in relation to what the injectors are doing. When you let off the gas the fuel is cut and the injectors are off so the display goes to max 99 mpg. when you floor it they are dumping in the gas display goes down 5mpg.

[Ray Moore]

Check your tires yet?

[ken1784]

<div class='quotetop'>QUOTE(exces6\";p=\"68915)</div>

Also, sometimes when I am coasting, the MPG doesn't go to 99.9 all the time, somtimes i get 70-90.[/b]

I bet you were at Stage-3.
http://www.priuschat.com/forums/kb.php?mod...de=article&k=14

Regards,
Ken@Japan

[efusco]

<div class='quotetop'>QUOTE(ken1784\";p=\"69021)</div>

<div class='quotetop'>QUOTE(exces6\";p=\"68915)

Also, sometimes when I am coasting, the MPG doesn't go to 99.9 all the time, somtimes i get 70-90.[/b]

I bet you were at Stage-3.
http://www.priuschat.com/forums/kb.php?mod...de=article&k=14

Regards,
Ken@Japan[/b][/quote]

Ding, ding, ding....we have a winner!!!

When the ICE is cold/in warm up it will not return to 99.9...I'm going to guess you're seeing this behavior mostly with a cold start and more than likely when you're running AC and/or defroster. Once warmed up completely you'll see 99.9 when off the gas.

The drop in mpg during acceleration should not concern you at all, it is normal.

[efusco]

<div class='quotetop'>QUOTE(Kyle Pehrson\";p=\"68960)</div>

I only use Chevron Gas 88 or higher.  Thats just me you can take it for what worth.[/b]

Could you walk me through your reasoning here Kyle. I'm, frankly, suprised to hear you use something other than the recommended 87 octane and have to wonder if you're doing yourself and your Prius a disservice by doing so.

[TonyPSchaefer]

Tires might explain a sudden drop in mileage. It did in my case. Now I'm diligent.

The "less than 99.9MPG coasting" might be a result of "behind the scenes" engine operation. I see this all the time. I don't know exces6's location, but when it's cold here, the engine will run to maintain the cabin heat or to warm itself after long periods of inoperability. Subsequently, even when there are no arrows on the display - or even when it shows regen - the MPG stays below 99.9. Remember, the MFD only shows the energy being used to power the wheels and the energy recharging the battery. I truly wish it would show when the engine is running to operate the A/C compressor when at a standstill, for example.

[edit]
The problem with opening multiple threads in multiple tabs in Firefox is that by the time I get to the latter tabs, a dozen people have already posted replies. Oh well. The more the merrier.