Two weeks ago, I took my Jeep in for some brake work. I patronized the place to which my company takes its vehicles (we have a fleet of about 28) for service. When it was returned, I was told that they had had to replace the rotors because they had gotten too thin (after about 134,000 miles) as well as the pads. The mechanic told me to go easy on it for a hundred miles or so to give the rotors and pads a chance to set. Little did he know - what he would think of as going easy would be insanely abusive to me these days.
But as I drove, the smell of burning brakes suffused the cabin. I could feel the brakes grab as I would attempt to coast to a stop. The instant mileage indication was at about 60% of what I had come to expect in any particular driving situation. OH NO!!! I'm burning fossil fuel to heat metal for no reason. My five tank moving average had been at 24.23 m.p.g, and my last two tanks were 21.98 and 20.36 m.p.g. The bottom line is that I'M WASTING GASOLINE! I was so horrified that I took the Jeep to the dealer to have them make sure the installation was performed properly. They confirmed that it had been and verified that, even after 400 miles, the symptoms I was experiencing were not unusual.
I believe that it's over now - when I let the car coast I feel no resistance and the numbers seem to be back where they should be on the display. But I now realize how sensitive I have become to the behavior of the car. Even after the smell of the brakes was gone and the car was close to being back to normal, I could tell it wasn't quite right. I'm conscious of every aspect of its behaviour by both feel and by the numbers. I think if there were problems with fuel injectors, spark plugs, etc. I would be able to quickly sense and remedy them.
Now it's back to trying to get the averages to 25 m.p.g. It's starting to look like that's the practical limit for this car. I'm going to change the air filter to
a more nonrestrictive after market type (Air Hog or something) to see if that has a measureable effect. My IT guy is very interested in that experiment but I had to wait until the Great Brake Job Catastrophe had abated.