CraigRL

I have been driving our recently purchased 1998 RL for 5 weeks and am on my 5th tank of mostly city driving - just South of L.A.

I have typically owned 4 cylinder cars. We have a 2005 Nissan Quest van with Nissan's 3.5 liter, 6-cyl engine (at 230 or 240 HP), which gets terrible city mileage. (My wife averages about 13. I can coax out 15.

Well, I thought the Acura RL would be much better, due to it's low RPMs, less weight (than the van), much less wind resistance, and Honda ingenuity. I understand the RL is rated by the EPA at like 19 city mpg (and 24 city), and I've seen posts of people getting upper teens in city driving.

However, here are the results of my first 4 tanks:

1. 12.9 mpg - with Mobil Mid-Grade. 100% town ("city") driving. Normal driving.
2. 14.6 mpg - with Costco Premium gas. 60% town driving / 40% freeway. Very conservative Grandpa style driving.
3. 17.5 mpg - with Costco Premium gas. 40% town / 60% freeway (including climbing to 6k feet, and coasting -- even in neutral -- back down.)
4. 13.4 mpg - with Costco Regular gas. 100% town driving. Mixed drivers, including my kids.

14.6 ave. mpg

Questions for other Gen 1 RL owners:

1. Have you noticed a difference in MPG based on using regular or mid-grade or premium gas? (The prior owner always used regular, he said.)

2. If Premium fuel is important (or required, as the gas tank note says), is it possible that having the car run on Regular gas for the past 80k miles could have clogged filters or something deteriorating or in need of attention that has reduced the MPG to what I'm getting now? (Note, there is no pinging or engine noise, and the car drives GREAT!)

3. Does it matter which fuel (i.e. Chevron/Mobile/Texaco or Costco/Valero/USA, etc.) is used, as long as it's Premium?

4. What's the trick to getting 19mpg in town/city, and 24 on the freeway? As you can see, I'm getting nothing close! My average is down 25-35% from advertized and what I expected. I am using some hybrid-hypermiling techniques (i.e. slow acceleration, braking early to avoid full stops, coasting whenever possible), taking some of the joy away from the driving experience. Still with lame results.

Love to hear how any of you pursued increased MPG and have learned secrets to getting more mileage per tank out of your RLs.

Thanks for your input!

MyNameIsEarl

Depending on what kind of city driving you do. Frequent stops will hurt your MPG.

1. The car is designed for premium grade gasoline. That's the octane rating that the engine expects for the compression in the cylinders and timing and all that jazz to be. Granted the cars computer can compensate, but you lose efficiency.

I get around 21-22 mpg, pretty consistently actually, no matter how I drive.

2. That could possibly have happened, although I've never heard of it. You may want to try a well known and highly recommended fuel additive a couple times and see if that helps.

3. All the gas stations are held up to the same standard, for all intensive purposes, they are the same.

4. I like to use cruise control quite a bit. It keeps the revs pretty constant and avoid any increases that would draw more gas out. I also drive 20% below the speed limit just because, too. At 65 mph, you may be running at 2500 RPM, whereas at 55 mph, you may be running at 2200 RPM. Less revs = less gas.

If you can afford it and if there are no other suggestions, you may want to have someone look at it and see what they can find. I'd caution though, this will be expensive, especially when there is not a very well defined problem such as a leaking radiator, broken transmission mount, etc.

CraigRL

I see some recommendations around the web to try Seafoam. I will pursue putting a bottle in the tank and see if there is any improvement.

Thanks for weighing in, MNiEarl.

I should note that most of my town/city driving is short commutes (2-3 miles), so the car's warm-up is quite limited. That said, it's been summer weather here (80-100). I'm running A/C (plus using the SunRoof cracked to vent air -- but mostly) shaded to not let in much sun. However, my highway driving was obviously well-warmed up, and I'm not even approaching anything close to 20+.

Ken1997TL

Low teens is likely in your area. Not surprised at all. "City" driving as defined by the EPA has a higher average speed than you are likely doing.

CraigRL

Ken -- What was your "city" mileage in Oregon on your RL?

re: "City" driving according to the EPA being a higher speed:

That's why I'm referring to my driving as "town" driving. It's really not like driving in Los Angeles proper (actual brutal "city" driving). I supposed I'm in busy suburbs. I'm driving generally 35-45 mph, with signals. 2-3 lane main roads that travel pretty well. It's not close to constant stop & go like downtown L.A.

Since my earlier post, I read of a number of reservations about Seafoam.
I went to O'Reilly's planning to get some BG44k. Couldn't find it. But they were featuring Lucas Deep Clean Fuel System Cleaner. So I got put that in today.

Trying also to use Windows more and less A/C. And even S L O W E R acceleration -- to see if anything changes.

Ken1997TL

When I lived in the burbs of Portland I got 16 mpg. In Medford which has fewer red lights, I got 18. In both cases, 25 mpg on the highway. I once got 26 driving to and from the Bay Area.

Does your A/C have an 'Econ' setting? My '02 did.

CraigRL

Yes. Using it.

GoStumpy

I'm in a lot of stop & go traffic to and from work, but manage to hit 80km/h for at least 2-3 km each way.. 15k total each way mostly in town.

No highway trips yet, and I'm averaging 18.5mpg (us, 22.5 UK MPG)

Using mid-grade fuel.

Refined Luxury

Living in the Seattle suburbs, I was averaging 16mpg doing daily driving from school to work and other trips here and there. It's always worse in the winter. During the summer with mostly city driving, I average around 21mpg. I've done two roadtrips (200ish miles each) this week and averaged 25.8mpg, but that was all freeway.

I've always been filling up regular at Costco.

onebadna1nsx

I use 91 all the time, gotta get the most out of it's decent performance figures. Getting 17-20mpg depending on how hard I drive the car.

Definitely give seafoam a try. Change your sparkplugs too. Maybe it'll help.

JMo717

I usually try to run a couple ounces of marvel mystery oil in my gas at every fill up. As people have stated tons of things affect gas mileage. Tires, fuel and air filter, plugs and even the engine oil you use. Since owning my RL the one thing that improved my MPG's by far was cleaning my clogged EGR port. It was so bad that my cruise control did not work because the EGR pipe to the intake manifold was so clogged it stopped the vacuum system from working properly lol