My wife is driving down the highway (right now as I post this) and is having an issue with the 07 using way to much fuel. She drives it back and forth to Miami from Orlando and only uses about half a tank each way, but she is right now about a half hour out and is already below 1/4 tank (I'm estimating that she has driven about 190 miles so far). She said that she has been driving between 70 and 80 mph the entire way (all highway) when she suddenly felt a shudder and the yellow engine indicator light came on. She pulled over and had the car in idle for a few minutes and the light went out.

Most of what I am reading in the manual is some emissions sensor error, but the message panel is not throwing a code for me to look up.

Any ideas? Right now I am torn between a bad Oxygen sensor, or a bad coil pack.

We did have an issue about 6 months ago with the engine at idle dropping below 1K revs and I ended up replacing all of the plugs, but not the coil packs, and it seems to have done the trick. But now my suspicions are that one of the packs went bad and that cylinder is just dumping fuel.

On the other hand, my wife says that the shudder is not constant which gives me pause in my theory of the coil pack/cylinder being dead as the engine would then be shuddering the entire time, at least that it my assumption.

 

It's a bad coil pack, most likely. It's more common for the ignition coils (coil packs) to go bad rather than the O2 Sensor. I had the same symptoms.

I replaced my coils with some really cheap 20 bucks coil packs and they didn't last too long (about 10k?). I recommend getting OEM (Hitachi) ones, they're like 50 bucks a piece from Rockauto.

Replace all of them if possible.