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Gas mileage sucks!


merlinx
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Hi guys, I have a 97 Pathfinder and my gas mileage sucks!!!! I know that these trucks suck gas but the highest I have ever goten is 14mpg :o . We went on a gross country trip and I averaged about 13mpg. I live in Southern Cali, SF valley and its been hot so I have been running the AC a lot. Is this normal? I filled up yesturday and I calculated 12.5 mpg. I recently changed the plugs and wires, fuel and air filter, I did the cold air intake mod and same thing. on my road trip I did use ac most of the way. Any ideas? I heard that these trucks get 19 on the highway and 16 on the street but I get nowhere near thatstudy- . Any help would be apriciated. thanks -

 

Jason

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Hi guys, I have a 97 Pathfinder and my gas mileage sucks!!!! I know that these trucks suck gas but the highest I have ever goten is 14mpg  :o . We went on a gross country trip and I averaged about 13mpg. I live in Southern Cali, SF valley and its been hot so I have been running the AC a lot. Is this normal? I filled up yesturday and I calculated 12.5 mpg. I recently changed the plugs and wires, fuel and air filter, I did the cold air intake mod and same thing. on my road trip I did use ac most of the way. Any ideas? I heard that these trucks get 19 on the highway and 16 on the street but I get nowhere near thatstudy- . Any help would be apriciated. thanks -

 

Jason

I think you might have answered your own question. If you are running the AC alot, your gas mileage will suffer. I hardly ever run the AC and on my road trips, I get around 16 on the freeway. I have 31" tires and a crap load of stuff in the back at all times like my sub box, tools, fishing rods, amps etc...

 

Try cleaning your MAF sensor and your throttle body too.

Edited by DJ Dank
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I dunno... I have bigger tires, the bumper, lift & the rack on the top - and I my mileage is no where that bad...

 

I suppose the AC will knock you down a bit - but I cant imagine that much??

How heavy is your foot?? You'll find your best milage is if you stay under 3000 rpm.

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Thanks guys, well I have 18" wheels with 255 55 r 18

according to the whel conversion web site the original size 235 70 15 the diameter is 27.95 and the new diameter with the new wheels 255 55 18 is 29.04. The funny thing on the spedo is that it used to read a little under now its right on according to my GPS.

As for the heavy foot, not that heavy really, I get bad gas mileage even on the freeway at 65-70 mph

 

any suggestions on how to clean the maf and throttle body ?

 

Do you guys think the tires would make a big difference? I do have a sub box and amps but thats it.

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I dunno... I have bigger tires, the bumper, lift & the rack on the top - and I my mileage is no where that bad...

 

I suppose the AC will knock you down a bit - but I cant imagine that much??

How heavy is your foot?? You'll find your best milage is if you stay under 3000 rpm.

Pezzy, what kind of mileage are you getting? With all that you're no where near that? Makes me weary when I think about lifting and getting my basket etc...then my mileage would even takea bigger hit.

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My mileage on my 97 4x4 se with 32" BFG AT's is at best 13MPG Highway. I think the original tire size was either a 28 or 29 depending on if you have an XE, LE or SE. So if basic calculatins mean anything, i hav a 2" lift with tires that are 3" at least larger than stock, which basically puts me 5 inches over stock with the stock gear ratio.....

 

When I bought it in 99 or 2000 i was only getting 15-17 on the highway!

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Also keep in mind if you increase the amount of air entering the cylinder, Cold air intake/K&N etc....the car now has to feed more fuel to mix with the increased airflow so the air/fuel mix stays right. Thats how you feel better throttle response and maybe even actually rear wheel HP increase when you do things like cold air intake, headers, free flow exhaust.....

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My mileage on my 97 4x4 se with 32" BFG AT's is at best 13MPG Highway. I think the original tire size was either a 28 or 29 depending on if you have an XE, LE or SE. So if basic calculatins mean anything, i hav a 2" lift with tires that are 3" at least larger than stock, which basically puts me 5 inches over stock with the stock gear ratio.....

 

When I bought it in 99 or 2000 i was only getting 15-17 on the highway!

I see what your saying, but do you think the lift would have any bearing on the mileage? From what I know I think only the wheel diameter would effect the mileage because the engine would have to work a little harder to turn the wheel. Why would the lift on the truck effect the mileage?

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88's write up on cleaning the MAF sensor is also a sticky in the How-To section of the Garage.

 

Its here...

 

Cleaing MAF

 

Although its for the older Pathy's, in concept, its really the same.

Thanks Dank, Cleaned out the MAF, there wasnt much to be dirty but I used some carb cleaner to clean the wires. I also sprayed some carb cleaner into the throtle body, some carbon deposits came out from the buterfly. I didnt want to take it apart couse I dont have the gaskets for it. Hope it helps. Thanks

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I see what your saying, but do you think the lift would have any bearing on the mileage? From what I know I think only the wheel diameter would effect the mileage because the engine would have to work a little harder to turn the wheel. Why would the lift on the truck effect the mileage?

Well I can't say from personal experience, since I'm not lifted, but it says lifting the car will decrease your gas mileage? Why? You're adding more wind resistence. Just like how adding a roof basket, or airdam will do the same...you're adding more wind resistance.

 

When you're lifted, you're increasing resistance.

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Well I can't say from personal experience, since I'm not lifted, but it says lifting the car will decrease your gas mileage? Why? You're adding more wind resistence. Just like how adding a roof basket, or airdam will do the same...you're adding more wind resistance.

 

When you're lifted, you're increasing resistance.

Exactly....The truck was designed to have a certain amount of resistance in its stock stance....the higher you go the more that resistance is altered.......Sorry im not an airflow specialist so that's about all I can figure

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Merlin...ever haul anything on your pathy before? Like a mattress? Or a canoe?Thats a perfect example. I had my 17ft canoe on the top of the pathy on a 300+ mile road trip and it was no fun...felt like a sail. Lots of resistance.

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So if basic calculatins mean anything, i hav a 2" lift with tires that are 3" at least larger than stock, which basically puts me 5 inches over stock with the stock gear ratio.....

 

Sorry, I dont think I explained myself correctly. I was addressing this part (quote) From what I understood you were saying that 2" plus 3" on your truck would be the reason why the mileage would decrease. I was thinking you meant that gas mileage would take a dump based on the height of the vehicle because of the bigger tires. I was not taking into account the wind and basic air resistance. I do understand now though. No accountng for the wind, Im ust trying to compare to your rigs. I figure my truck is stock height and the tires are only about a little more than an inch higher than stock. I have no cage on top. Pretty stock vehicle otherwise. I just cant figure out why the bad mileage. The pathy runs great, engine is strong, no vibration, steady as a rock. Hopefully the cleaning of the MAF will help.

Jason

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Pezzy, what kind of mileage are you getting? With all that you're no where near that? Makes me weary when I think about lifting and getting my basket etc...then my mileage would even takea bigger hit.

*gets out the calulator & online conversion website*

I get about 15.5 - 16 mpg, thats mixed city & highway driving...

SO I guess it's not as good as I was thinking...

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Still working on it Dank, I semi cleaned off the throttle body and the MAF (I sprayed it with carb cleaner then used compressed air to dry it) and now im looking into maybe changing the water temp. I read on another post that sometimes this is the cuprid. I also borowed a code reader from auto zone but thre were no codes. I figure I want to do this this weekend and test it out Sunday or monday. Any more input?

 

seems like I should be getting at least 15mpg

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Alright, I filed up yesterday and managed to drive just 34 miles. I filled up to the brim today and calculated the mpg. so far it was 15.5. not the greatest and probably not the most accurate but it gives me high hopes. wil post later on next week when i go through a full tank. I really hope changing the coolant sensor worked. I would hate to do the O2 sensor removal and claning. there are 4 of them!!!!!

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  • 2 weeks later...

My guess would be your rims. You mentioned you're running 18" so you've got a lot more mass that needs to get rolling compared with the stock rims. If you have your stock rims and tires, maybe swap them and get a mileage count for a tank on those.

 

Also how big is your sub box? I didn't notice that much of a change when I add my amp and single 10" box.

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Box is small, 2 10". As for the wheels slight possibility but I dont have the sock wheels to swap. The tires as of a lower profile and the spedometer is rigt on so I dont know. Not too happy about it though. Truck runs excelent though.

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