Bad Gas Mileage Update

[Diabolic1]

After throwing a CEL for code PO420 Catalyst failure I thought I was getting bad gas mileage due to a clogged cat or bad o2 sensor. The CEL came on for one run cycle and never returned. Today I did some highway driving and got 28mpg with the A/C on and averaging between 65mph and 75mph or basically 3000-4000 rpm. No cruise control was used because of mild traffic. Does this sound reasonable? Should I still be concerned? I figure with the cruise "on" and the A/C off I could get about 30 mpg. I'm right at 90K miles, so should I pony up the cash for new spark plugs?

[jtyler05si]

i have stock 40,000 miles. all oil changes but two have been done by me...therefore, no reason for anything to be wrong in it and it runs great.

i get about 27...a/c on or off...cruise on or off.

28 is a good number, i think...some people get more some get less

[Diabolic1]

It must be bad in town driving habbits for me. I'm seriously getting about 20 mpg! The 1st 2 days I owned the car I got 25mpg in town driving like I stole it! Now I granny the car shifting at 2500-3000 rpm and it's getting worse! Maybe I should drive it hard again. maybe it likes to shift a 4000 rpm between gear changes??

[socmex7]

yea, my ep averages 25-27 mpg even when i baby the shit outta her.. all engines are not built alike even when they're the "same" engine. it's just a lottery basically... some people here get 35 mpg while some average 20...

[socmex7]

It must be bad in town driving habbits for me. I'm seriously getting about 20 mpg! The 1st 2 days I owned the car I got 25mpg in town driving like I stole it! Now I granny the car shifting at 2500-3000 rpm and it's getting worse! Maybe I should drive it hard again. maybe it likes to shift a 4000 rpm between gear changes??

i read somewhere that when you shift too low your engine actually works harder because there's not enough torque to push the car... i'll try and find the thread but i remember someone saying that between 3500-4000 was the "best" so to speak for fuel economy due to our power curve.. someone correct me if i'm wrong though :mangel:

[Rep]

It must be bad in town driving habbits for me. I'm seriously getting about 20 mpg! The 1st 2 days I owned the car I got 25mpg in town driving like I stole it! Now I granny the car shifting at 2500-3000 rpm and it's getting worse! Maybe I should drive it hard again. maybe it likes to shift a 4000 rpm between gear changes??
Check tire pressure and alignment. Oil change, valve adjustment, fuel filter. Also, if you've bypassed the thermostat your gas mileage will go to poop.

[jtyler05si]

yeah i remember someone saying that it says to shift @ 3500 in the book.

[Diabolic1]

Check tire pressure and alignment. Oil change, valve adjustment, fuel filter. Also, if you've bypassed the thermostat your gas mileage will go to poop.

So where is the fuel filter? Under the back seat in the tank? Can I buy just the filter? Should I change the plugs at 90,000 miles? I'm changing the oil this weekend. Honda filter and 5W20 Castrol Syntec. Installing a drop in K&N as well. I will check the tire pressure. What does everyone recomend? About 40psi per tire?

[benkieboy]

i get 25 highway. when i get 26, i am happy already. and i drive conservatively everyday.

[Rep]

So where is the fuel filter? Under the back seat in the tank? Can I buy just the filter? Should I change the plugs at 90,000 miles? I'm changing the oil this weekend. Honda filter and 5W20 Castrol Syntec. Installing a drop in K&N as well. I will check the tire pressure. What does everyone recomend? About 40psi per tire?
On most cars it's on the firewall, not sure on an EP. Should be able to grab one at a basic autoparts store? Anyone have firm info on this?

For better gas mileage, some people over-inflate their tires by 3-4 psi. The more air in the tire, the smaller the contact patch, thus less rolling friction.

[socmex7]

the recomended psi is in your driver door jam... if you're on stockies then i believe it's 30 psi, if you over inflate you wear out the center of the tire faster than the sideways and increase the chance of a blowout on the freeway because you wont see the wear on your tires because your sidewall will look fine (what people usually judge tread on). i see it a work all the time, people complain that they don't ned new tire because they have plenty of tread on the sidewall but they're showing steel in the middle of their tires...

[gehjl]

I drove to see my gf, who lives 3 hours away, 2 weeks ago. I set my cruise control at 65 mph the entire trip. I was honked, I was tailed, I was passed, I got nasty looks. I get to her city, I fill up my tank 35 mpg :mbiggrin: (was full when I left, filled it again, divided how many gallons it took by how many miles I went). Then I completely wasted an entire tank around the city and driving home. With City + Highway I got 32 mpg. But I baby the hell out of the driving. It takes me a while just to get to 20. I get honked :mrolleyes:

Pure city, the best i got was 28

[QDRHRSE]

I don't know how you guys get such shitty mileage. If I get less than 28 I get worried. I'm mostly on the highway but I drive at least 30 miles of canyon a day.

[socmex7]

mmm 30 miles of canyon.. haha

[Diabolic1]

I bought the car to have a little fun and get better mieage than my 5.0 mustang. My stang gets 24 on the hwy and 17mpg in town. Seems like at the current rate I made a bad decision. I want to get this squared away. I might install a boost guage/ Vacume guage and drive to achieve the highest vacume readings per gear. That would def improve my mileage.

[kwiksi]

I get about 28mpg city/highway with my K20A2.:mcool: I used to get 14-15 mpg with my RX7 TurboII.:meek: