Bad MPG After Accident

We’ve lost 30% MPG after a minor fender bender! (From 16.8 MPG to 11.8 ) No engine damage was done only body damage. It’s a 2004 Jeep Cherokee. We’ve taken it to the dealer and they found no obvious fuel leak and their computer diagnostic revealed nothing. Please help! Thanks!

Front end damage? do you notice any difference in high speed behavior, vibration, whatever?

You should get an alignment check. Your hubs may have remained locked but I don’t know if that is even possible on a Jeep. If the accident happened before the cold weather set in, Winter may be the cause. A CV joint may have tightened up, a wheel bearing may be bad or a brake could be siezed.

Some more info is needed.
Where was the vehicle hit? Front, rear, etc.
How is mileage being determined; by the gauge or the fill and check against the odometer method?
Any Check Engine Light ever come on?
Does the engine idle smooth?

If the mileage has really gone south, and even if the CEL is not on, I would suggest dropping by a local AutoZone, Advance, Checkers, etc. and have them scan the vehicle. They will do this for free and sometimes an outside opinion does not hurt.
If you get any codes post them back here for discussion.

So sorry I have not responded to your responses!!! Been out of touch due to medical issues in the family. Here’s the rest of the information…
-no front end damage, driver door replaced
-no check engine light or fault codes
-no difference in high speed behavior or other performance
-we are checking mileage by BOTH the gauge, and the fill and check against odometer…we used to get over 300 miles per tank and now we’re getting a little over 200!!!

We’ve taken it to the dealership twice…they can’t find anything! They hooked it up to their “computers” and can’t find any errors…they can’t find any obvious fuel leak…the oxygen sensors are OK according to the computer…they contacted chrysler for assistance and performed an O2 sensor heater test…the vehicle is performing as per factory spec.

I think part of the problem in diagnosing is that nobody believes us!!! The weather hasn’t changed (we’re in sunny Miami Fl.) and we’re using the same fuel as always.

We’re desperate…it’s costing us a fortune in gas! Help!! I’ll send home made cookies to whoever can solve the problem!!!

Where was the car hit? How fast? It’s amazing how little a bump can cause significant damage to an engine.

Driver’s side was hit changing lanes…going about 15mph…any thoughts?

difficult to conceive of anything that would change the mileage that much and not affect the performance or handling of the car.

The guauge is woefully inaccurate. I wonder if a placebo effect is in place. Run a few tanks and then decide.

You’re correct…it’s difficult to think of anything that would affect the MPG without noticing a change in performance…I think that’s why nobody believes us. We’ve tracked 3 full tanks…the in the 1st we got 196 miles for 19.1 gal…the second, we got 218 miles for 19.3 gal (we had a road trip which included some hwy miles)…the third, we got 230 miles for 18.9 gal (again, had a road trip which included some hwy miles). It’s a mystery…but an expensive one…there has to be something that’s using too much fuel.

Can oxygen sensors cause too much fuel to be used, even if there are no fault codes showing on the computer. Also, I read (on the internet) about someone that had a fuel leak that was very difficult to detect because the fuel was evaporating quickly.

I’m not a mechanic but I know something is wrong…we constantly checked the MPG read-out and it dropped drastically after the accident.

Any thoughts at all…no matter how obscure…will be appreicated…

did your percentage highway driving go down? from trips to the dealer? Could it be locked in 4WD?

we have not been doing alot of hwy driving, but we used to get 19.5 to 20.5 mpg highway driving. I believe we only have 4wd option…high or low…what else? least you guys are thinking a whole lot more than the dealer…thanks so much

Check for a leak in the fuel lines, maybe around the filter, or tank. The gas is going somewhere, maybe the tank or filler tube is leaking.

get it on a lift with the ignition on, then check around the fuel lines for leaks. Ignition on to pressurize the system. I think this would work. You should be able to hear the fuel pump running.

Or without a lift, just leave the ignition on for an hour or so, then see if you smell gas?

Am I correct that with ignition on, not started, the fuel pump will run?