[KeemoSaabi]

Strangest problem.
My 05 Arc 2.3T has the trip computer, my mileage is usually 18-20 mpg. I noticed it went way down to 12-14 mpg. I kept resetting it, but it kept averaging back to the same thing. I also noticed it felt considerably FASTER. I had tried racing a Dodge Hemi Magnum in the past and it pulled away from me easily. Then I recently tried again, and was a much closer race. It also would serioulsly squeal the tires through an intersection if I floored it, whereas before it would just bark them a little bit (if I turned TCS off). Cool problem to have!
Then, opposite. Started showing 26 mpg, and power is way down. Bummer.

What could it be? I had no warning lights. Boost pressure guage seemed to act normally. Same fuel was used.

 

[Guest]

I used to notice that my car would pull harder before it warmed up. Obviously beating on it is not a healthy thing to do but it makes sense that colder exhaust will help with turbo spool as will colder temperatures- I estimate optimal running temperature to be somewhere between 35-50 degrees F. I remember being able to squeal the tires in second on the right day before the car warmed up fully and on others it would just bog down. If you want that kind of power all the time swap in the td04.

As for mileage change your spark plugs and air filter. Your mileage should not be that low. A malfunctioning MAF sensor can cause poor mileage. This will sometimes fail to trigger a check engine code but the dealer will be able to see abnormalities with a tech II.

 

[Raven18940]

but it makes sense that colder exhaust will help with turbo spool as will colder temperatures

Actually, it's the opposite, the cold exhaust makes the turbo longer to spool cause it's cooling the exhaust charge, robbing it of energy. Now why does it feel faster, that's probably cause it's running an increased throttle angle when cold to compensate for it's actual poor running. Or at least that's my best guess, I've never noticed my car faster when cold.

I too would look to the spark plugs first, the DI likes new plugs at least once a year, twice if you can bother.

 

[SectorNine50]

I think your car was just asking for a TD-04.

...or a GT28...

Boost control valve could've been malfunctioning, map sensor could've been malfunctioning, maf could've been malfunctioning, iat sensor could've been malfunctioning... pretty impossible to say, I've never diagnosed too much power before...

If it ain't broke, don't fix it! (It's expensive and frustrating... )

 

[Guest]

I think your car was just asking for a TD-04.

...or a GT28...

Boost control valve could've been malfunctioning, map sensor could've been malfunctioning, maf could've been malfunctioning, iat sensor could've been malfunctioning... pretty impossible to say, I've never diagnosed too much power before...

If it ain't broke, don't fix it! (It's expensive and frustrating... )

And also under warranty. Ahh i remember those days... Let it be the dealers problem now and not his problem later... Worth getting it looked at i would say. My MAF took a dump at about 35k and was making the motor run wicked rich. If you see any black gunk around your tailpipe it would suggest a problem. If i hadn't gotten everything fixed on warranty id be a few grand poorer.

 

[SectorNine50]

And also under warranty. Ahh i remember those days... Let it be the dealers problem now and not his problem later... Worth getting it looked at i would say. My MAF took a dump at about 35k and was making the motor run wicked rich. If you see any black gunk around your tailpipe it would suggest a problem. If i hadn't gotten everything fixed on warranty id be a few grand poorer.

That is very true, wonder how the dealer would respond to "Is there a speed fairy?" :lol: