: Sudden 10% MPG increase



the Sandman
01-19-04, 02:01 PM
Here's a strange occurence - a sudden 10% or more increase in my fuel economy (MPG) for no apparant reason. My '02 STS has 24,000 miles on it, and has had all GM and dealer recommended maintenance performed. I'm running Mobil 1 motor oil, and the car is completely bone stock. Last oil change was about 2,500 miles ago. I noticed the change staring within the last week or so, as reported by the dash display. Under the same conditions as always, with no change in driving style, instantaneous MPG at 70 MPH on level ground has gone up from 21 to 24, and avg MPH for the last tank is 19 MPG, the usual being low 17's up until now. I put on 85+ miles per day and the increase is definitely there for whatever reason - I always keep an eye on that readout...

Any ideas what could be causing this? Erroneous readout? Engine break-in?

MMNineInchNails
01-19-04, 02:23 PM
extra weight taken out perhaps? not flooring it as much? if nothing like that changed, you know that right before an engine is about to explode, it gets the best performance. :lildevil: or maybe you just put better gas in...?

the Sandman
01-19-04, 02:33 PM
extra weight taken out perhaps? Nope
...not flooring it as much?No change in driving style at all, nor in type of driving done.
...if nothing like that changed, you know that right before an engine is about to explode, it gets the best performance. :lildevil: :crybaby:
...or maybe you just put better gas in...?Same gas as always...

Stoneage_Caddy
01-19-04, 03:01 PM
i had a similar increase but it was due to chage of driving route , pretty much 95% highway now

spose the engine is finally broke in ? also it has been cooler this week , perhaps the climate controll computer isnt cycleing the compressor as much ?

the Sandman
01-19-04, 03:09 PM
i had a similar increase but it was due to chage of driving route , pretty much 95% highway now

spose the engine is finally broke in ? also it has been cooler this week , perhaps the climate controll computer isnt cycleing the compressor as much ?It's actually been warmer the last week or so that it had been. I don't think that's it - nice try though... :D

Ralph
01-19-04, 11:04 PM
It's actually been warmer the last week or so that it had been. I don't think that's it - nice try though... :D

Actually I was going to say climate also. We live in such a varying climate up here from -40 to +40 C. In the winter I notice any car I've had has much more power, and uses more gas. Something to do with the more dense cooler air molecules or something. In warmer climates, or if it has got more hot in the last while, the opposite would take effect, better gas mileage, but less power.

New air filter? I've read car mags that mention the factory "break-in" period of 1000 miles is a joke!! Expect much better mileage and proper break-in around 15-20,000 miles!

When I installed Plat. plugs in my 5.0L Merc, along with a K&N air filter, at first I picked up 5 or 7 more mpg. The problem with this is, though, I found that mileage dwindle away because I was more heavy footed enjoying the extra power, and sound of the engine.

What is your mileage?