RL = Sluggish
 

Lately, I have been noticing that my 07 RL is very sluggish. The low-end torque seem to be lacking. I'd hate to "floor" it every time I need more instant power... gas is not cheap.

Also, I noticed that I am averaging almost 18MPG and on the highway, I can't get any higher than 24.5 MPG. Does this seem right to you?

Lastly, my RL shakes like a wet dog (feels like it, anyway) when I am on the highway. I just had an alignment done and a road-force balance about a month ago. I am leaning toward warped wheels... any suggestions to all three "issues"?

shakes=bad tires (maybe flat spotted somehow) or bad bushings somewhere

maybe its time to do your spark plugs

How many miles are on it?

or a whole tune-up in general

I have less than 48,000 miles on it.

Through my dismay, I drove it very aggressively a couple of days ago for about 150 miles, and it seem to have "loosen" up the vehicle. Maybe the ECU was "informed" that I'd like it to be a bit more peppier?

It could be...

try doing a ECU Reset some say that the ECU learns how you normally drive. i notice that the throttle response is much better after a ECU reset

Just remember to keep your radio/navigation codes handy.

I am happy to report that the RL is a little peppier, at an expense of a 2 MPG loss.

Any DIY for reseting the ECU?

I would swap out the air filter for a K&N. You will notice a bit quicker on the throttle response, and because it breathes easier you might pick up a bit on the gas mileage. Are you running synthetic oil? That helps more than you can imagine. :)

Disconnect the battery for a minute.