So, the past two tanks I have been getting about 23 MPG, when I usually get 26 MPG. What gives? I didn't drive my car any harder than I usually do, but the sudden change in gas mileage DID come after acura replaced my dipstick tube. Any ideas? Should I reset the ECU?

 

I notice a definate loss of milage when it goes from kinda cold/warm to really cold.

Figure the ECU has to run warmup enrichment longer, and colder air means more O2, which means more gas needed.

 

I would guess weather. I actually picked up 3mph leaning out my interstate cruising RPM's (4000-5500) at partial throttle. The ATS put me down around 21 mpg and the leaning out put me back at 24 mpg (City and highway miles)

 

I think you've found the answer Watson. Seriously, who cares? 3 mpg is no big deal...the car is just fine...probably has to do more with temperature, humidity, and driving habits than anything else.

If you were getting 10 mph during city driving, then I'd be concerned...but I average 24 so 23 doesn't seem like a big deal.

 

Over the past 2 months I've been getting lower mileage as well. I think it has something to do with the weather. Or at least I'm hoping it does...