Car is acting differently since trip

Hello my dear Prius mentors,

I recently took a weekend trip and drove about 400 miles. I have had my Prius for about a month and a half and have put about 1800 miles on it in that time. Before my trip, my MPG average was about 52. The trip caused it to drop to 49.5. Although my MPGs dropped, I was still pleased to get that average when driving at around 70 MPH the whole time.

Well, since my return, I've been driving my usual routes and I'm not getting as good of an MPG average as I was getting before my trip. The car is also acting differently. Usually, when I leave home in the morning and the engine is cold, I am able to drive in stealth mode upon leaving my subdivision (takes about 56 seconds to get there, I suppose). Now, I can no longer drive in stealth at all on my way out of my housing development and most of the trip to my son's school and to work, like I used to. It wants to run the ICE, even when the battery is charged up and the engine should be warm. I'm not doing anything differently than I did last week on my routes. I'll take my foot off of the accellerator to try to get into stealth, but the ICE immediately kicks in (a little frustrating). After about 10 minutes of this, it will finally let me stealth. It's as if the engine is taking longer to warm up. The weather has not been colder, still fairly warm (65-75 degrees, depending on time of day). I usually get about 55-60 MPG on my way to work in the morning, but now I can no longer get that and MPG has stayed at 49.

Can anyone explain this? I want to get back up over 50.

I've already been told by my friend who also has a Prius that I'm obsessed with my MPGs. Maybe so, but she is only getting 45 MPG...

 

Yes. I filled it up on the way home on my road trip. You know, the pump said "less than 10% ethanol." I was going to check on that because I seem to recall some posts here about ethanol, but I forgot about that until you mentioned the gas. Would that be a factor?

I will check my tire pressure. I haven't done so since I first changed them to 42/40 the day after I bought the car.

 

Well, I've not been running the heater or air conditioner. Even with the air conditioner on in the past, however, I could stealth from the stoplight leaving my housing area. Now, I have to wait 10 minutes into my trip to do so. Something changed.

 

Sounds about right. I'm doing everything I was doing last week, but the ICE is acting differently. Wants to be on all the time for the first 10 minutes. I will, however, be mindful of coming to a complete stop. I have several stops on my route (stoplights, stop signs, other drivers, etc.). Thanks for the info.

 

Umm...yeah, that is certainly possible. I've never reset my MFD. I've only had the car for a little over a month, though. 49.6 is my lifetine average, everything and the trip included. I thought I should leave it as is, so that I would keep my lifetime average displayed. That's the reason why it hasn't climbed up yet, I'm sure. However, my MPGs have been consistently lower with my ICE engine running more.

Also, I do have ethanol gas in the car (less than 10%, according the pump.

I will definitely check the tire pressure again and avoid ethanol-laced gas in the future, but I still don't understand why the ICE is being so stubborn about running longer. If I have the battery fully charged and I've been driving it for a few minutes, it should let me stealth, right? That is the main thing that's bothering me. It wasn't doing that last week, but it is now. After about 10 minutes, it will let me stealth, but before then, it stubbornly comes on when I am trying to stealth drive. Last week and before, it would let me stealth after approximately one minute. My drive to my son's school and to work is mostly 30-35 mph driving, so I can potentially get a lot of stealth driving in if the ICE will lay off. Maybe it will get back to normal in a couple of days - perhaps it is some kind of fluke after its first long trip. Before the trip, I had not run it at speeds over 60 mph for any consistent length of time. My trip was three hours each way and ranged between 65-70 mph.

Thanks for all your input, everybody.