Just purchased 04 RL and problem
 

I just purchased an 04 RL Navi from my mom. The car has 68k miles on it. I have replaced timing belt, all accessory belts, and all filters in the car. However I am getting very poor gas mileage. When I mean poor, I mean like 16-17 mpg. I filled up using premium (that is all that has ever been put in it) and I was only able to go 255 miles before the needle was dead on the E line. I just had an oil change done on the car and the service advisor at Acura dealership said that it may need a valve adjustment and that could take care of the low fuel mileage problem. I have run a couple of cans of injector cleaner (Seafoam) through it but no improvement. What is everyone's thoughts on this? Am I expecting too much?

you're expecting too much! i average 14-16mpg around town and 20-22mpg on the highway.

I'm only getting like 17 to 18 on highway and even less in town. From what I've read and after talking to a client of mine who owns one I thought I should get around 18-20 in city and 22-23 on highway?

Have you changed the plugs? The most i have ever been able to achieve was about 23 MPG, on the highway, doing probably 70, with cruise control on for 95% of the trip. I get about 16-17 mpg city, depends on how hard i drive.

15-17 is about right for city (remember the car weighs 3800+ lbs). 20-22 hwy.

I don't think a valve adjustment would have anything to do with fuel consumption, would it?
I get 270-280 to a full tank.

Don't Forget Your Tires
 

Also make sure your tires are properly inflated.

That is normal...unfortunately. Don't let the V6 fool you, it drinks like a V8. But like was said above, it's a heavy car and the V6 has to work hard. My V6 2009 Camry with the same 3.5L displacement got 23 City 30+ Hwy but it was a lighter car, very plastic feeling. The RL is substantial and needs to eat a lot. ;) It's not an economical car really, it was designed for class & luxury. If great fuel economy is something that is important for you, then the RL probably won't fit the bill.

The RL is far from being economical.

I got better gas mileage in my Lexus GS400 (4.0L V8) than I do with the RL.

Oh well. Lexus wasn't paid off, the RL is so it doesn't really bother me that much.

Ouch.:what: I've found the fuel economy to be best when keeping the revs under 2500 rpm. I'm glad the RL doesn't have a peaky engine that requires you to rev the daylights out of it. The torque peaks at 2800 rpm, so it always feels strong IMO.

Winter gas and cold weather have a significant impact too.:ugh:

What's the redline of 1st Gen RL. You can always install an intake or K&N drop-in filter to add mpg/performance.

^^ Around 5900 I think. This engine has the lowest redline out of all the cars I've owned.

Our redline is so low, it's almost in diesel territory:tomato: Most VW diesels redline around 4900rpm. Yeah, 1K makes a difference LOL

WOW!!! That's low for Honda's.

Lowest out of any gasoline-powered Honda engine. Its a very stroked motor with valve timing tuned for torque.