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.

 

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. 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.

 

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 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.