When i first got my 2012 C back in April for the couple of tanks I was getting 54 then 56 mpg. then I started to see a decline. Now I'm getting between 50 and 52 mpg. I have not changed my driving style at all. Any idea as to why the constant decrease?
But it likely wasn't working NEARLY as hard in April as it is now. And the hot dry summer air itself cuts down the engine efficiency just a tad. You didn't by any chance change the place you normally buy gas did you ??
YIKES. Didn't notice that before. If that is 48 "cold", I don't think that is a good idea in a place like you live. Have you ever checked the pressure say at 5 PM after being out in the sun all day ?? Pressure T'HAT high can't be good for tread wear or traction. And another thought: If your mileage continues to decline, you might want to get the 12 V battery tested. A weak battery can cause all kinds of strange things.
for someone driving with AC constantly 50-52 sounds about right. That's almost right on the factory listed numbers. I wouldn't panic unless it dropped to the mid-low 40s, then just take it in early. I'm willing to be you just drove it a bit more moderately early on as most people do with new cars.
Fuel economy complaints/queries? Please copy, paste & answer these questions, esp. if you're new All those warmup factors ought to be rolled into the needed safety margins used for setting the sidewall max pressure label. If that label says 51 psi, he ought to be OK. Why not?
Do I really want to reply to this.......?? I probably shouldn't since it looks like you have been on here for 5 years and should know the answer already. GROSS over-inflation, in this case ~13 pounds over the recommendation which is 37% over, often causes the center of the tread to wear faster than the edges.......or depending on the alignment, one side faster than the other. In addition to that, it makes the tires pretty much rock hard, the tread and sidewalls doesn't flex like they should and it's hard on the suspension and more prone to damage on a hard hit (like a BAD pothole). If they were set at 48 in the morning when the temp was say 60 F and then the afternoon temp goes up to maybe 100 F.........the resulting pressure after driving a bit could be around 58. It is a matter of opinion if that is really bad or not......and maybe how bad. It is also a matter of conjecture whether or not going more than +5 really helps that much anyway. They make those recommendations for good reasons; influenced by consideration for comfort, wear and safety. I don't deviate THAT much. Your opinion might be different.
My guess is combination of A/C and sklowly drop in gas energy as the refineries gear up fotr volume over energy contect. See if it rises next fall.
