What's up with my MPG?

[MattDyer94]

Hey guys, I recently purchased a 2wd '97 Limited which I'm loving, however, it *appears* that I'm getting around 14mpg and it's stock except for the tires which are 265/75/16. These shouldn't be hitting the mileage THAT much?

So what the heck should I do to get it back to where it should be?

The gas station is cleaning me out! :smashputer:

 

[cordrayj1]

Drive it like a granny. And don't use bad gas stations.

Sent from my MB860 using Tapatalk

 

[A.Wilson013]

Without a CEL, I imagine. Fuel economy is a strange issue... I would start with your basic tune up... Clean air filter, clean MAF, clean throttle body, spark plugs, wires... Sea foam if you believe in it.

 

[MattDyer94]

Drive it like a granny. And don't use bad gas stations.

Sent from my MB860 using Tapatalk

I drive this thing like there's an egg between the pedal and my foot haha. Just curious..bad gas stations? Is kroger bad....?

Without a CEL, I imagine. Fuel economy is a strange issue... I would start with your basic tune up... Clean air filter, clean MAF, clean throttle body, spark plugs, wires... Sea foam if you believe in it.

Does Sea foam actually do anything? I've seen people post about it but honestly don't know the purpose. I'm set up to take it in for a tuneup next week. I'll get all that stuff taken care of.

Hopefully it'll bring the mileage back up..I haven't even had a chance to get beefy tires or a slight lift..definitely won't if I can't bring my mileage up :violin:

 

[IanB]

If you can find fuel that doesn't have ethanol in it, you should get a big bump in economy using it over E-10 crap you get at most stations. Also, make sure your tires are properly inflated, and you are accounting for the difference in rolling diameter when doing your fuel economy calculations so you are comparing apples to apples.

 

[MattDyer94]

If you can find fuel that doesn't have ethanol in it, you should get a big bump in economy using it over E-10 crap you get at most stations. Also, make sure your tires are properly inflated, and you are accounting for the difference in rolling diameter when doing your fuel economy calculations so you are comparing apples to apples.

I had no idea it made a mileage difference..I figured it just effected overall life of the vehicle. Would a ScanGaugeII do the job for getting a precise calculation?

 

[HCurphy]

Without a CEL, I imagine. Fuel economy is a strange issue... I would start with your basic tune up... Clean air filter, clean MAF, clean throttle body, spark plugs, wires... Sea foam if you believe in it.

I would add OEM fuel filter, possibly front O2 sensor, check tire pressure, and unrelated to fuel economy--but change your pcv valve, too.

Also, seafoam is a petroleum based cleaning product. Cleans injectors and generally removes carbon/sludge deposits. I like seafoam, I've heard/read that BG44 is better though, albeit more expensive. (seafoam never seemed to help my mpg's but it definately can smooth out your idle)

edit: also insure that your check engine light is functioning properly--basically in comes on when you turn the ignition to acc. I say that because a clogged cat could also lead to poor mpg's as well but if that were the cause I would expect a CEL

 

[IanB]

I had no idea it made a mileage difference..I figured it just effected overall life of the vehicle. Would a ScanGaugeII do the job for getting a precise calculation?

Ethanol is a huge crock, it actually takes more energy to produce than it provides, thank the corn lobbyists, they do good work it would appear. Ethanol has less energy content than gasoline, so by adding 10% ethanol to our fuel, you get less energy potential in the same volume of fuel. And ethanol is corrosive to many rubber components in the fuel system.

The scangaugeII will give accurate calculations if the data it is basing those calculations off is accurate. If the larger tires causes the odometer to read low (you cover more ground with less tire rotations than stock), then the miles you will show per tank on the trip meter will also be low = mpg will read low.

I run those same size tires, and my speedometer is actually MORE accurate than with the stock size tires according to GPS, but the mpg will show a drop because the odometer was OVER reporting before the tire change. My current MPG figures are more accurate than before, but read slightly lower as a result.

 

[HCurphy]

Ethanol is a huge crock, it actually takes more energy to produce than it provides, thank the corn lobbyists, they do good work it would appear. Ethanol has less energy content than gasoline, so by adding 10% ethanol to our fuel, you get less energy potential in the same volume of fuel. And ethanol is corrosive to many rubber components in the fuel system.

The scangaugeII will give accurate calculations if the data it is basing those calculations off is accurate. If the larger tires causes the odometer to read low (you cover more ground with less tire rotations than stock), then the miles you will show per tank on the trip meter will also be low = mpg will read low.

I run those same size tires, and my speedometer is actually MORE accurate than with the stock size tires according to GPS, but the mpg will show a drop because the odometer was OVER reporting before the tire change. My current MPG figures are more accurate than before, but read slightly lower as a result.

I went from 235/70 to 265/70 and most of the time I run with the E-10 mix, my uncorrected milage is still usually 17-18 in town. I don't think those would be the sole causes--but certainly could be contributing factors.

 

[brian2sun]

The scangaugeII will give accurate calculations if the data it is basing those calculations off is accurate. If the larger tires causes the odometer to read low (you cover more ground with less tire rotations than stock), then the miles you will show per tank on the trip meter will also be low = mpg will read low.

In the setup menu on the SC2, you can adjust it for tire size and then the trip meter and mpg will read accurately. I'm running the SC2 in my Taco. Stock tire size is 225/75/15, I'm running 235/75/15. I adjusted the speedo up 2% and it's dead on now. The SC2 tank trip meter reads 102 miles when my stock odometer reads that I went 100 miles.

 

[IanB]

In the setup menu on the SC2, you can adjust it for tire size and then the trip meter and mpg will read accurately. I'm running the SC2 in my Taco. Stock tire size is 225/75/15, I'm running 235/75/15. I adjusted the speedo up 2% and it's dead on now. The SC2 tank trip meter reads 102 miles when my stock odometer reads that I went 100 miles.

Good to know, they seem like great tools these SC2's. My truck is OBD0 or I'd have one for sure.

 

[brian2sun]

Wow, the Surfs aren't OBDII? That sucks. I thought all vehicles '96+ were OBDII. I guess that's just cars sold for American market?

 

[4-Ripcord]

I would replace the front O2 sensor. When I hear of people taking hits of 5+ mpgs, its almost always the O2 sensor. After you replace it, do the rest of a small tune up and reset the EFI fuse.

 

[IanB]

Wow, the Surfs aren't OBDII? That sucks. I thought all vehicles '96+ were OBDII. I guess that's just cars sold for American market?

Nope, which sucks in that I can't use a SG2, but on the other hand I don't have or need a cat, or any other emissions equipment. The only thing electronic about my powertrain is the injection pump, there's no feedback loop. On the other hand, it would be even better if I had a mechanical pump, lol.

 

[A.Wilson013]

Check this out to find nearby Ethanol Free gas stations...

Ethanol-free gas stations in the U.S. and Canada

 

[Gerdo]

What type of trips are you driving?
If I just drive up to the local stores, a mile away, my gas mileage sucks too. I'll get ~10-12 mpg (read by my scangauge). This is due to the cold engine that will run rich till warmed up and the stop and go.