Sudden drop in MPG
12-11-2008, 09:06 AM
#27
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People, keep in mind that the "colder" temperatures he's talking about is low 70's high 60's 
The engine not warming up as fast is not the issue. It has nothing to do with the ambient temperature, and I doubt it has much to do with the "winter gas" either. Even in the worst conditions 10 MPG is far below "normal."
It's under warranty, I would take it to a dealer if you have one nearby that doesn't suck (fat chance, right?). Something is wrong. I'm really surprised it still runs well and hasn't thrown any codes... are you sure it isn't leaking somewhere?
It should be pretty easy to smell if it is.
The engine not warming up as fast is not the issue. It has nothing to do with the ambient temperature, and I doubt it has much to do with the "winter gas" either. Even in the worst conditions 10 MPG is far below "normal."It's under warranty, I would take it to a dealer if you have one nearby that doesn't suck (fat chance, right?). Something is wrong. I'm really surprised it still runs well and hasn't thrown any codes... are you sure it isn't leaking somewhere?
It should be pretty easy to smell if it is.There's usually a smell of gas when I start the engine, but after it warms up (a minute or two), the smell goes away.
I was rather hoping I wouldn't have to drive to dealership, but I'll bite the bullet I guess.
And finding a good dealership is like finding a Best Buy with reasonable prices for electronic equipment
I've tried taking gas from a few different stations, but I didn't notice any difference
12-11-2008, 09:55 AM
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I doubt the dealership can do anything for you. I'm in Florida also, but I haven't noticed any difference in gas mileage or blends. My commute is also short (8 miles) and the worst I see is 18 MPG around town and 23 MPG if it's strictly highway. It might be your driving style. I do all my shifting at about 3k though.
Some simple checks would be the air filter, catalytic converter, tire pressures, although it would be unusual for any of those things to be clogged at such a low mileage car.
Some simple checks would be the air filter, catalytic converter, tire pressures, although it would be unusual for any of those things to be clogged at such a low mileage car.
12-11-2008, 10:09 AM
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12-11-2008, 10:19 AM
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I doubt the dealership can do anything for you. I'm in Florida also, but I haven't noticed any difference in gas mileage or blends. My commute is also short (8 miles) and the worst I see is 18 MPG around town and 23 MPG if it's strictly highway. It might be your driving style. I do all my shifting at about 3k though.
Some simple checks would be the air filter, catalytic converter, tire pressures, although it would be unusual for any of those things to be clogged at such a low mileage car.
Some simple checks would be the air filter, catalytic converter, tire pressures, although it would be unusual for any of those things to be clogged at such a low mileage car.
I put some air into my front tires, but they were barely missing any pressure.
I'll check the filter and cat tonight.
Yea that's what I figured, cool
12-11-2008, 10:47 AM
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Good luck. It's really hard to diagnose these things sometimes. The only thing is to backtrack and see what has changed since last time. I don't use synthetic, just regular Castrol GTX 10W-30 and don't do any premix or anything.
Are you actually calculating the MPG at each fillup (i.e. dividing miles travelled by gallons put into tank) or are you using a rough estimate? Although I don't write it down, I always use my phone calculator to compute the MPG at each fillup and try to use the same technique to fill up the tank (2nd click of pump after first auto shutoff).
Are you actually calculating the MPG at each fillup (i.e. dividing miles travelled by gallons put into tank) or are you using a rough estimate? Although I don't write it down, I always use my phone calculator to compute the MPG at each fillup and try to use the same technique to fill up the tank (2nd click of pump after first auto shutoff).
12-11-2008, 11:06 AM
#32
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Good luck. It's really hard to diagnose these things sometimes. The only thing is to backtrack and see what has changed since last time. I don't use synthetic, just regular Castrol GTX 10W-30 and don't do any premix or anything.
Are you actually calculating the MPG at each fillup (i.e. dividing miles travelled by gallons put into tank) or are you using a rough estimate? Although I don't write it down, I always use my phone calculator to compute the MPG at each fillup and try to use the same technique to fill up the tank (2nd click of pump after first auto shutoff).
Are you actually calculating the MPG at each fillup (i.e. dividing miles travelled by gallons put into tank) or are you using a rough estimate? Although I don't write it down, I always use my phone calculator to compute the MPG at each fillup and try to use the same technique to fill up the tank (2nd click of pump after first auto shutoff).
12-11-2008, 12:07 PM
#33
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and no i dont mean the one on your dash
the one thats on your engine adjusting the coolant flow to the engine.
image from rx8strakes
it sits in the housing
which is connected to your raditor hose
12-11-2008, 12:27 PM
#36
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[quote=zoom44;2764190]answer please[quote]
Did, https://www.rx8club.com/showpost.php...1&postcount=27
Answer is: yes
Ahh I see, kinda figured it wasn't the dash one
I'll see if I can get home early enough to not be too dark outside so I can check things out
[quote]Did, https://www.rx8club.com/showpost.php...1&postcount=27
Answer is: yes
Ahh I see, kinda figured it wasn't the dash one
I'll see if I can get home early enough to not be too dark outside so I can check things out
12-11-2008, 12:33 PM
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I am having the same problem in Atlanta (with almost identical mileage variation as the OP). Most days, I only drive between home and work (which is about 3 miles). In Atlanta, that can vary from 10 minutes to 30 minutes (but mostly on the 10-15 minute range). With the cold weather we have had for the past month (and I only drive in the morning and the evening), it is possible that my engine management has me operating in closed loop for less than half of my trip on most occassions. Would that plus a shift to winter blend result in me getting around 10 mpg?
12-11-2008, 01:04 PM
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12-13-2008, 03:03 AM
#40
I'm up here in Daytona Beach, only had my 8 (04) for a month. I attributed the first two, or three, tanks that seemed to drain quick to having fun. This last tank I tried (a little) to not accelerate so quickly, etc to gauge the mileage I was getting, ended up getting 13mpg after filling up today.
Mine has 10,700 miles, 500 of those I put on. Haven't added any more oil yet but have been checking it. Fill up at 2 different Hess stations, about 10 miles apart depending on when the light comes on.
Let me know if you find a cause, I'd be interested to know.
Mine has 10,700 miles, 500 of those I put on. Haven't added any more oil yet but have been checking it. Fill up at 2 different Hess stations, about 10 miles apart depending on when the light comes on.
Let me know if you find a cause, I'd be interested to know.
12-14-2008, 12:13 AM
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My car also has a terrible smell of gas in the morning. I have been averaging 11mpg and that is the *****. Mind you it is really cold where i am, -30 celcius this weekend 
, car didn't start this morning. Best i have got in town driving has been about 170 miles, usually 150 or less now. Best i have got on the highway was 360 miles on all highway.
, car didn't start this morning. Best i have got in town driving has been about 170 miles, usually 150 or less now. Best i have got on the highway was 360 miles on all highway.
12-14-2008, 12:08 PM
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Yea, it's pretty much always smelled slightly of gas when I start her up, it's not like "WOW this reeks of gas" but rather a "kinda smells like gas don't it?"
12-14-2008, 03:35 PM
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may be unlikely that the thermostat is stuck open... its a rather new car, and owner hasn't reported that the dash temperature gauge does not move to the normal operating position.
if his fans ever comes on, the PCM may also most likely be operating in closed loop.
So the question... does your temp needle go to the normal operating position and does your fans turn on after a few minutes of idling?
if his fans ever comes on, the PCM may also most likely be operating in closed loop.
So the question... does your temp needle go to the normal operating position and does your fans turn on after a few minutes of idling?
12-15-2008, 01:26 AM
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There's no reduced performance though.
Needle goes to normal operating temperature depending on how fast engine heats up (depends how hard I drive obviously) and then stays there. Fans activate as needed, and will sometimes stay on after I turn car off if it's a really hot day and stuff.
may be unlikely that the thermostat is stuck open... its a rather new car, and owner hasn't reported that the dash temperature gauge does not move to the normal operating position.
if his fans ever comes on, the PCM may also most likely be operating in closed loop.
So the question... does your temp needle go to the normal operating position and does your fans turn on after a few minutes of idling?
if his fans ever comes on, the PCM may also most likely be operating in closed loop.
So the question... does your temp needle go to the normal operating position and does your fans turn on after a few minutes of idling?