Horrible Gas Mileage

[gibbo80]

i just got 24 and mine has never had sensors cleaned or replaced and it has 152k now

[240dreams]

alright. old mpg: about 12 mpg, 200 miles per tank. now after adding stp complete fuel system cleaner and new 89 octane shell gas: 300 mpg

[rousie13]

I'm getting roughly 20 mpg or so. When I get my car back out next year when I get home from school, a lot of the sensors and such are being replaced with a full tune up. So hopefully I'll get a little better gas mileage.

[i2ice4m3]

alright. old mpg: about 12 mpg, 200 miles per tank. now after adding stp complete fuel system cleaner and new 89 octane shell gas: 300 mpg

wow 300mpg! you can buy a new car with the money you save on gas!

[TurboKA37]

hey trpower7, how much did i cost to do that tune up? how much was the cost of the sensors u replaced and where did u buy them?

[180fan]

Check your gas cap also. I am now getting better mileage since I've replaced my gas cap. My old cap wasn't making the psssshhh sound when I uncapped it.

[trpower7]

I bought them all at Nissan, but I get a price break because I am a tech at another dealership. Total, I probably spent sub-$200 to get it all done, that's of course doing all the labor myself. Coolant temp sensor and checking voltage on MAFS and TPS, eliminated AIV, carbon cannister, (I know these don't affect mileage), plugs wires cap and rotor, seafoam a few times through the vacuum system, I always run 93 Octane gasoline, Mobil1 Synthetic engine oil, Redline trans and diff oil, ghetto-fied short intake, etc. If you are getting really bad mileage O2 and Coolant Temp sensors are the first things I'd change, you can get both for less than $50.

[goshoryuken]

I changed the fuel filter on my 240sx, I also changed the o2 sensor, I'm running 89 gas, I used The Outlaw fuel injector cleaner and now my car is getting roughly 17mpg where it used to get 15. It not much of an improvement. My last fuel injector is leaking a bit, I might need to change the O-rings on all of them (they're really cheap I hear), and that will help. I'm also going to keep using fuel injector cleaner for a while, still have to get a new distributor cap, wires, plugs, and distributor rotor. Does getting an oil filter help? Well, I've pretty much given up on better gas mileage for now, when I find a definite answer to my 15mpg problem . . . then I'll try it, otherwise to me it's not worth the time and money.

[TurboKA37]

well u should be changing ur oil filter every oil change anyway.

[s14a]

i have a 98 and i get like 250 on a full tank30k miles, engine is all stock

[Jookmasta]

you should be gettin alot more s14a. i have a 93 with 118k and im pullin around 340 on a tank.

[trpower7]

This is really bad, but I uncapped the smaller vacuum line that connects into the intake tube when I fabbed up a short intake and I believe it leaned the engine out substantially. Since I always use 93 octane I dont' believe it's detonating, I hear no knocking or pinging and timing is still dead on. Power is up substantially, as we all know the engine is tuned slightly rich from the factory (note: when I say substantially I mean I actually feel a bit in the seat of my pants). Mileage is around 420 miles to a tank. The S13 has a 14 gallon fuel tank. You do the math.

[Toahk]

s13 has a 15.9 gallon or so tank I think actually.

[Toahk]

So doing the math your getting 26~ roughly trpower7

[Rockenreno]

I got 335 miles on 13.9 gallons last fill up in my 95 240sx. This is about 50/50 highway city driving. To think, my tank is 17.2 gallons... thats a whole 3.3 gallons or ~80 miles I could have gone!

(I get around 26 mpg... 30-31 on the freeway)

I run Chevron Plus most of the time. Not sure what Octane it is here... 89 or 91. I figure the extra $1.30 is worth it)

[TurboKA37]

i dont understand y people use lower octane gas. in the long run the extra dollar or so pays itself off. benifits: better gas mileage, engine runs cleaner, engine runs smoother, engine runs safer, engine produces more power. downside: cost. there are alot more good things than bad when buying higher octane gas. a question: i read sumwhere that in england they only sell a minimum 97 or so octane gas, is this true?

[Toahk]

I dont know about you, but here where I live the highest octane gas cost about 2.20 a gallon, while the 87 octance is 1.75. thats 45 cents Per gallon , so that equals about 7 dollars more Per fuel up. In the long run that adds up, and imo a few octane isnt going to do anything really, do you actually notice your car running better and more powerful from a whopping 4 octane gain or whatever. I sure dont but thats just me, these cars arent performance cars and its not reccomended to run the higher octane.

[llamabeta]

I have 92 S13 and when I open the fuel lid it says "Premium fuel is recommened for maximum performance."

Just thought I'd throw that in.

[Toahk]

On my 89 s13 is says "UNLEADED FUEL ONLY"

[trpower7]

Everytime I fill my S13 up when the fuel light comes on I can put roughly 13.5 gallons in. 420/13.5 = 31.1 mpg IN THE CITY. I'm also running 20W-50 motor oil which lord knows doesn't help with the mileage issue. The last time I took a long trip I clocked a 5 mpg increase with cruise set at 70mph for roughly two hours. Even if the figure is slightly less now, it would still yield around 35 mpg. By the way, Nissan said our cars should get 24 city, 28 hwy MPG. Thank God in Tennessee premium is 93 octane and only costs about 15 cents more than regular 87............

[TurboKA37]

wow toahk a 45 cent difference?round here its like a 25 cent dif. and yes i do feel a difference when running a higher octane

[goshoryuken]

I think I'm going to convert to 93 instead of 89. I get 12mpg on 87 octane, about 17mpg on 89 octane . .I should get 20+ on 93 octane. But the point is . .on regular . .its supposed to be at least 20. :-\ I get paid tomorrow, so I'll drive around until empty . .then use some fuel injector cleaner . .and fill up the car with 93 and then drive normal and I'll update you guys on the mileage after that.