So, today, my roommate had to drive to his job to get his schedule, and he asked me to come with him. Being the good Motorist that I am, I insisted that I drive him. He agreed. I had to turn around in a private road leading off of my street. I ended up stopping parallel to the street, blocking the private road, waiting for the traffic to pass so I could pull out. Once it did, I pulled out into the street, but unbeknownst to me, I wasn't going to clear the curb. I ran over it, and as the car passed, there were two huge impacts to the underbody. We both exclaimed "holy s***," and I turned into the first side street I came to to inspect the car for damage. I was positive I crumpled the rocker panels at least. When I looked at the car, however, there was zero damage that I could discern, on the body, or underneath.

Since then, my OBC has been acting very strangely with regards to the gas mileage display. It was displaying an average of 27 in the city, but after the mileage dropped to 22. I reset the computer, the mileage then hovering around 14, never going above 17. It's behavior also changed; Instead of reflecting a change in mileage every minute or so, it would show it change every few seconds. Every few seconds! I was watching it plummet from 22 to 14 MPG in under a minute. Just now I took the car out for a spin; the mileage was slowly climbing, but very slowly, so I reset it again. The mileage seemed about normal for the duration of the trip, sitting around 27 when I turned off the car. When I turned it back on, the mileage was at 25, and dropped to 22 again by the time I got it home, 15-20 minutes later.

My questions are:

1) Could today's interaction with the curb have caused my OBC to go haywire? Everything it's doing is strange. Since I replaced the air filter, it has never dipped below 26 MPG until now.
2) Or, is the OBC accurately reflecting the mileage, indicating that I damaged something important?

This is all pretty upsetting, so any insight will be appreciated!

 

Whenever you reset your obc average mileage it will be erratic for a while. It won't stabilize until you have more miles on it. When I fill up, mine can go from 50 down to 15 during one acceleration from stop. Let it go for 75 miles or so. If it's still erratic, then get it checked out.

ps. you shouldn't expect to get much better than 17 while driving over curbs

 

Let me get this straight, you are 2" above the road and STILL couldn't see the curb? Actually, I pulled the same stunt today. Thank God no one was with me to give me THAT look of "this is how you drive?" Hope your car wasn't damaged in anyway, that would sux BIG time!!