ok, so I got home today and I checked my trip odometer.. (I reset it every time I get gas) 170 miles.. and I was at less than 1/4 tank!I havent done any racing on this tank, or even random spirited driving that could have brought it down. My car's performance feels great with my injen intake and wsp Y and the below freezing temps but im wondering if something might be wrong, since im basically getting around 13 mpg and that was all highway . I recently had new platinum plugs put in at the dealer as well as a new fuel filter if it saves a reply to get a tuneup.

 

Check for leaks around your fuel filter.

 

Are you confident in your math skills?
Did you maybe reset the trip odo sometime AFTER the fuel stop?
Could someone else have?

Is the trip odometer measuring correct distance? (trip-odo distance-travelled matches odo-distance-travelled?)



Your car would have to be exhibiting some pretty noticeable driveability issues to average that low. Someone I know towed a 5x8 Uhaul box trailer behind a 4th Gen. with a total loaded weight of about 1,900lbs and averaged about 16.9 mpg on a highway trip.

If your math is right, something is very wrong with your car.

I'd try to duplicate the same mileage results on your next tank & go from there.


In the meantime, you could check:

spark plugs - look for signs of misfire or odd coloration. Lightly sand the electrodes. Blow off any sand residue. Check & adjust gap. Reinstall.
ignition coils - check for resistance using a multimeter
air-filter - need replacement?
grounds - loosen & retighten battery & ignition ground bolts to freshen up the contacts.
PCV valve - check for proper function & replace if neccessary.

 

check if your knock sensor needs to be replaced as well.

 

Wouldn't you get a computer code if your knock sensor was bad?

 

how are you doing the math? i hope you're not just assuming that the fuel level gauge is accurate. go fill up with gas and use your odometer or trip(whichever) until you need gas again. Go back to the SAME gas pump and pay attention to how many gallons you put in. Now do the math.

 

no. do a search on knock sensor.

 

If you are not pulling any codes from the ECU, I would say its the cold temps that causing the poor mileage. The engine runs very rich until it gets up to operating temp.

I have gotten as poor as 15mpg in the city before, and it was always during the winter.

 

Not quite...

You'll pull a code for a bad KS (0304), but it wont light up the CEL.

 

That's exactly what I said. No light.

 

I get really bad milage too. I get about 230 to a tank. I drive pretty hard but not constantly. Could this just be from driving hard or is there something wrong?

 

[Dr Evil voice]

Right....

[/Dr Evil voice]

 

i filled up today and i had about 220.......and i dont remember driving hard....i do let my car idle sometimes to keep t warm and sometimes i let it run and i get stuck on the phone and i forget its running so maybe thats y i ddint get as many miles...im 19 now and i got the max when i turned 16 and i remember getting like 300 miles no problem. my care has not had a tune up in 3 years.....its got 80k on it...ive only done 30k miles with it. i think i need a tune up with fuel filter and air filter

 

ok usualy with my 95 auto I get around 150 miles at the half tank point, now I am getting around 100 thats horribleI wasn't even driving hard with it I kept it all under 4k RPM

 

This may be a reason why a ban on cell phone usage in vehicles may be a good idea!

Dave

 

I drive hard most of the time, and was getting about 230 as well....I got a nearly free tank of gas once, so i decided to drive easy the whole time...needless to say, i was nearing 200 by HALF WAY.....i couldnt take it anymore tho, and i started driving hard again, so i only ended up somewhere around 300...

 

ok, mr moderator who wants gxe badges...do a SEARCH and find my comments on similar topics!

 

i didnt mean on teh phone in my car....i meant if i start ym car during the winter to warm up and i get stuck on the phone inside my house sometimes i forget and it runs for liek 30 min before i realize that its on.

 

I know this sounds trivial, but check your tire pressure. It's cold out and chances are you have lost some pressure because of it. Low tire pressure accounts a little for poorer gas mileage.

 

It has to be the cold...I just filled my tank up for 175miles and I used 11.8 gal. thats like 15mpg and prob cause of the cold, I let it warm up alot before I drive it, and i delivered it in the other day 80 miles...so its all good in the cold

-Matt

 

i don't think cold weather can affect mileage that much...
im up in canada, where we've been getting -15 to -27*C and i get about 190 miles (300km) when the needle is at half.
this is with 100% city driving, and hella messed up alignment!
most of the time im late for school...so im booting my car trying to be on time

 

wow, thought this thread was dead .. thanks for the replies btw.

 

...because I haven't seen more than 20 MPG in MONTHS!!!

In fact, I just came back from a long-ish trip and averaged only
18.5 MPG --> I averaged about 80 mph, and did go for one high-speed
run...

All the same, I've done the following in the last 6-8 months:

-- new PCV
-- new intake
-- new fuel filter
-- new OEM plugs (well, more like a year ago)

and I still get shiddy mileage...any ideas????

FLO_BOY

 

In the winter, if you do a lot "cold starts" and stop and go driving, you're gas mileage will be pretty bad. Letting your car idle to warm is horrible. An engine will warm up much faster when it's under easy load. In the cold, start your car and let it idle for 30-60 seconds, then start driving. Keep the RPMs below 3000rpm until the engine is fully warm (do not run your heater until the gauge comes up above the cold mark). An engine runs very rich when the motor is stone cold. Letting it idle to warm up takes 3-4 times as long therefore your engine will require a lot more fuel to warm up plus you're risking clogging your cat with the rich fuel ratio.

If you have an auto your mpg will be worse.

How are you doing your mileage math? You can't do it by looking at the gauge. You have to calculate it using what you put in and the miles you went. Example: You fill up completely with 18 gallons. You go 300 miles and then fill up again and only add 16 gallons to top off the tank. You went 300 miles on 16 gallons. 300/16= 18.75 miles per gallon.

You said you went 170 miles and only had a 1/4 tank left? I can usually go another 70-80 miles on a 1/4 tank and I'll still have 2-3 gallons left in the tank when I fill up. If your car is like mine and the gas gauge goes down slowly in the final 1/4 tank, then you're probably looking at 240-250 miles with 2 gallons left in the tank. Overall, you're looking at ~16 mpg which is still pretty low, but not unheard off if the temps are cold, your car spends it's life parked outside, and has a lot of cold starts and extended idling.

I have a 96 SE 5 speed with the typical bolt-ons and lighter weight 17s. In 15-25 degree weather, I'm getting approximately 22-23 mpg in 100% highway driving. On the street, I get ~20mpg and that's with lots of WOT 2nd fun. When the temps get up above 60, I get ~10-15% better mileage.

Like Street Reeper said, check your tire pressure. If you have large rims and/or wider tires, that too will negatively affect your mpg. I'm seeing about a 1 mpg loss with wide 235/45 17s.

A tuneup will do you little good unless you've got a CEL showing that you've got problems. The VQ needs very little tuning or maintenance to run efficently. We don't have to adjust valves, change timing belts, check timing, etc. A tuneup for a VQ includes changing fluids, filters, plugs, rotating tires, and checking for wear.


Dave

 

Yo Dev, I believe the cold is causing my mileage to plummet (plus my Nokians), and I'm in Toronto too. Don't trust that 300km @ half tank, if you keep driving, you'll notice how fast the other half tank disappears . During the warmer months I used to average 30mph with spirited driving. This cold snap has dropped me to 25 at least.

 

I'm AutoMagic

I remote start my car every day about 5 min. before I leave. (love that)

I drive 50/50 city/highway

60,000 miles and no tune up yet, all original equipment still under the hood.

I average about 22 MPG, on a trip I get about 28 MPG.

I also have California Emissions on my SE-L.


Go figure......