aspasia wrote:
> On Tue, 11 Mar 2008 01:41:21 -0700, aspasia wrote:
>
>
>>Anybody suggest why?
>>
>>I only put about 4K on the car since I bought it 1-3/4 years ago with
>>92K on it. I mostly drive around town, but also take the freeway to
>>"blow it out".
>>
>>Lately I notice the needle dropping like lead. I can't afford to go
>>anywhere, with these gas prices!
>>
>>I took it back to CarMax and they did what they call a tune-up,
>>which is just replacing the spark plugs. Is that a tune-up?
>>They *did* put in platinum plugs, supposedly better?
>>
>>I also had them replace air filter, fuel filter and change the oil.
>>
>>$$$$ and mileage is no better.
>>
>>What else could be keeping mileage so low?
>>
>>Tx
>>
>>Aspasia
>
>
> You guys have been way kewl in identifying the sensor problem(s)!
> I thanked you earlier, and want to do so again.
>
> I am relieved to learn this is not a major $$$, so I can go to my nabe
> mechanic with advance information..
>
> I discussed this long distance with my son (who knows about cars), and
> he wondered why the mechanics at CarMax hadn't done a simple test with
> the diagnostic gadget that reads out problems. I told him I didn't
> know WHAT CarMax mechanic had done; all I know is that they
> replaced the spark plugs and changed the oil, air, and fuel filters.
> So when I take the car back to CarMax (so they can fix the antenna
> they bent), I will try to find out whether they did a diagnostic test,
> and if so, what data it yielded..
>
> QUESTION: One poster suggested I use high octane (91) gas; said lower
> octane is harmful. This has been argued back and forth FOREVER. I
> don't mind spending the extra $$$ if there's any serious research
> validating his point. Is it purely a matter of opinion, or can
> anyone refer to such "serious research"?
>
> Again, thanks, amigos - your advice much appreciated.
>
> Aspasia
I don;t know if you've noticed, but it's been all me with the responses:)
Anyway, to answer your questions:
First, a computer diagnostic sometimes will not reveal a problem such as
this one. These are issues where sensors go semi-bad, but not fully
enough to trigger a code. I have expreienced this in several nissans
(Maxima, Altima, Sentra, Quest) with coolant temp sensors and O2
sensors. The sensors don't go bad, they just go "funny."
Secondly, as for what octane your car takes, refer to the manual. It wil
state that for maximamum performance, that includes for gas mileage, 91
octane or higher is better for the car. The Maxima's computer *will*
adjust to take advantage of the better fuel.
Try a tankful of super and drive normally. Then when the tank empties,
fill up with 87 octane. If everything else is equal, you will see that
the tankful of super unleaded gave you better gas mileage . . .enough
to offset the higher price of 91+ octane.
CD
|
