So my 2010 RX used to give about 350 miles on a full tank (14.xx gallons). I keep a close eye on this during every refill which is about once a week. (long commute since last year)
for the last 4 weeks I am getting about 280 miles on the same full tank and refill routine.

What I have noticed is that while going downhill I get significant drag and I tested to go into Neutral on a downgrade where the car should be accelerating, but I can feel a strong drag.
Before anyone starts to harp on me changing gears while in motion, I only did this a few times to check if the "drag" is real or my imagination.

Incidentally, my '09 Honda Pilot is doing the same, so I am asking for help.

TIA

 

Do you live near the ocean? Salt water can cause components to corrode. Maybe you have a caliper that is dragging or something along those lines.

 

I live in Bay Area, recently replaced my brakes after I started to notice the drag. I have checked my brakes again, my suspicion is on the parking brake which I also loosened up, but it is not helping.
It feels that the engine is also struggling and I was thinking to replace the Fuel filter and spark plugs, but have not gotten to that yet. I have now 110k miles

 

Wild guess - dragging caliper. Look at rotors, is any one of them blue-ish color?

 

Just feel your rotors after driving a bit. Even after 10 miles of light stop and go traffic, you shouldn’t feel any heat at all. If any are hot, that’s the offending caliper. My last original caliper on my 2010 is getting replaced this week.
Once, I had one of the pistons sticking so bad, it wouldn’t even move when idling In “D”.

 

Continuing the brake not retracting ... have you kept up with brake fluid purge schedule? Color of brake fluid in the reservoir is just one indicator, but the issue is with the fluid in the plumbing (tubes etc). It is frequently the most ignored service item.

Testing the drag in "Neutral" was indeed a great idea. Just in case some one else wants to do it. The can Stop at in incline and Shift into N. The word of caution is you should know that you are testing the brakes .. so have a plan incase you have a total failure .. specially if you have been driving and the brakes have become hot.
I prefer stopping at a flat driveway and have some on at the wheel. Move to "N" and then push the vehicle. You should expect that you are fighting the inertia, but if the vehicle digs in (tips) then it is the brake. Once it moves then inertia should make it roll a bit once the push force is removed.
Sure test is by jacking each wheel, chalking 3 other wheels and spinning with trans in N.


Drop in MPG can be due to other reasons too .. like the change in environment .. example: A/C use due to heat, traffic pattern, gas.

Salim
PS: Thread title was indeed attention grabbing.

 

Thanks! the title does bring people to the thread.

I do monitor my MPG religiously and often test the mileage by maintaining driving habits between fill-ups. I put a sticky on dash to remind what "habit" I am testing. :-)
I did test the driveway roll down and spinning wheel/s while jacked up and I do not hear or feel any resistance.

I'm facing same issue with my Honda Pilot.

 

Well, having two otherwise bulletproof cars do same problem somehow does not point towards cars. One - meh, maybe. Two? Nahh... there's something else to the story. Like real low tires pressure. Rolling on winter tires.. just shooting guesses out.
So did you touch rims after driving or look at the rotors colour?

 

Agreed! Yes, when it is happening to both cars there is something wrong. I got new tires on RX about 5 weeks ago, Honda has about 15,000 miles on them: I always put 5 lbs extra pressure and check them regularly, have an air compressor in the garage,
I touched the rotors after driving about 20 miles and yes, they were kind of cool that I could touch them, I cannot tell the color difference to me it is metal color, maybe a little blue.

Both cars are about 10 years old, the only thing I can think of is maybe Fuel Filter or Spark plugs.
BUT both items should not create a noticeable drag while running.

BTW where is the fuel filter on the RX?