Scraped bottom on a speed bump - now MPG is suffering.

Leading out of the gate: I am mechanically-retarded. So I just have to set the expectation low because I'm simply looking for guidance.

Last month I purchased my first Taco ('12 DCLB V6). Because I'm Type-A, I keep a mileage and MPG log and update it at every fill up. Since I purchased it I've been getting 18.1-18.4 MPG per tank.

HOWEVER, earlier this week I had to drive from RI to VA for a funeral and once arriving in VA I bottomed out the truck on a speed bump. Ever since then (on the trip back and 1 tank around town) I've been getting 16.8-17.3 MPG.

Does this sound right? What normally scrapes when you go too fast over a speed bump? I haven't gotten it on a lift yet, don't see any visible damage, and will be taking it to the dealer for another unrelated issue (bad weatherstripping) - what should I point to or suggest to look at? Or am I being too fickle?

Thanks for any and all guidance.

 

How did you bottom out a truck on a speed bump? Wtf?

 

Wasn't bottom out as much as scraped the bottom of the truck right behind the front tires - I didn't accelerate but wasn't on the brake either.

 

right a 4x4 bottoming out on a speed bump? how

 

Could you of damaged the catalayic converter?

 

Explain? Remember, car retarded. It WAS about 15 degrees colder in VA than RI... if that makes any sense.

 

You've probably never been to northern Virginia. They have speed HUMPS there in addition to speed bumps.

 

If you bottomed out the suspension, any scraping you heard was probably just the mud flaps hitting the speed bump. My mud flaps would scrape the speed bumps occassionally at my old apartment complex. There's nothing else low enough on the truck to scrape over a speed bump. As far as the MPG loss, it's likely just due to the highway run. I typically experience a drop in MPG on extended highway runs also. When you get back to your normal routine, your mileage should go back to where it was.

 

It sounds like you scraped the stock (ridiculously long) mud flaps on the speed bump. I doubt any structural part of your truck actually touched the speed bumps.

 

Probably scraped the mud flap? And, as mentioned, winter fuel blend could be the reason for the drop in mpg

 

You know, that's a great point. I looked all over the running boards and undercarriage but never checked the mud flaps... I love this site.

 

There is a cross beam between the two main frame rails, be about middle of cab, just behind/ under the back of the engine. If you hit something it'd probably be that. Check for scrabbing damage on it. It'd be easy to see.

Your mileage drop sounds consistance with the switch to winter fuels @ gas stations. I wouldn't be concerned unless it drops lower. Since your vehicle is brand new, you should get a slight boost in mpg's after your engine has broken in. Around 7,000 - 10,000 Miles.

 

I was completely unaware of the winter fuel blend - gonna have to google that. BUT, that cross beam that you mention was the first thing I checked when I got underneath it and didn't see anything at all.

I'm willing to bet my paycheck that it was the mudflaps (my memory of the sound is consistent with what plastic scraping vs. metal scraping would sound like). I just have to wait until lunch for me to run out there and look for the rub marks.

 

Yea scraped/damaged mud flaps can set you back 2-3 MPG, (thats why most guys take them off anyways) but if you get a sweet rockstar or monster sticker to put on the rear window it should get you back up to your normal mileage, and will even add 5-10 horsepower!

















But for real you seem like a nice enough guy so don't take that joke personally. I'd say its winter fuel mix like stated above.

 

There's not enough room on my rear window with all of the Hello Kitty decals I put on before my trip.

 

not sure about the ethanol part...

winter fuel was around before the idiots in DC started pushing the corn gas on us.

and, I believe the percent of ethanol must be posted on the pump by law.

use more than 10% on some vehicles and it will mess them up good. Even the 10% plays havoc on many boat motors and fuel tanks/fuel systems.

Ethanol is one of the dumbest things ever.

 

You hit your mudflaps. The two aren't related.

 

Haha that's your problem. The stickers are too much added weight, ruining your mileage. Problem solved.

 

Different states, different brands, different gas, different mpg. Not all gasoline is made exactly the same so it could just be VA gas vs RI gas.

 

This would be the only time in history Rhode Island didn't suck the worst out of all the states. I should inform the media.