whats wrong with my coupe?

[Hussain]

ok so something is wrong with my altima coupe. it drives 100% perfect, excellent performance, feels fast and everything but my MPG is crazy low! lol now i know everyone's thinking "slow down then" but its not because of my driving style. the other day i drove back and forth to Davis to meet up with Aaron and i set my cruise control at 65 or 70 and reset my MPG gauge. it read 27 MPG the whole time.... 27 isnt bad (EPA estimate is 26) but a year or 2 ago if i would have done the same exact thing, it would have read 32-35 MPG.... in the city i'm getting about 16 (sometimes a little over, sometimes a little under) when i used to get 19 consistently. it would only drop to 18 if i drove really really aggressive.... also, lately ive been smelling a burning smell. BUT the burning smell could be the wire from my cut-out because i disconnected the power but didnt take off the actual cut-out yet so the plastic wire may be touching the metal piping and causing the smell....

[QR25DE]

I suggest resetting the ecu by disconnecting the battery for 10 minutes.

Also make sure everything is connected. It may just need a tuneup. Check spark plugs, etc. Not burning any oil are you? Have you added any weight to the car? (Such as subwoofers, stereo stuff or any other things like heavier wheels?).

Have you gained weight? :P

How many miles on the motor now compared to last year or the year before?

[76er]

Canadian units.

I get about 800-825 kms per tank. (I once filled up with like 20-30 kms left on the range with the odometer reading i've already driven about 800 kms since my last fill up)The tank is like 70 litres825/70 = 11.70 litres/ km = 27.7 mpg

Thats doing 99% highway driving. Thats as good as its ever been for me.

[headhunt3r]

Canadian units.

I get about 800-825 kms per tank. (I once filled up with like 20-30 kms left on the range with the odometer reading i've already driven about 800 kms since my last fill up)The tank is like 70 litres825/70 = 11.70 litres/ km = 27.7 mpg

Thats doing 99% highway driving. Thats as good as its ever been for me.

- Your tank is actually 76 Liters.- The range remaining on your car display is quite inaccurate. I've driven it past the --- point before for quite a bit.

Best way to self calculate your mileage is to reset the trip meter after filling up. Drive for a "tank". Go fill up, and take the amount you fill up and divide that by the trip meter number, then multiply that by 100 to get your L / 100km.

[Hussain]

I suggest resetting the ecu by disconnecting the battery for 10 minutes.

Also make sure everything is connected. It may just need a tuneup. Check spark plugs, etc. Not burning any oil are you? Have you added any weight to the car? (Such as subwoofers, stereo stuff or any other things like heavier wheels?).

Have you gained weight? :P

How many miles on the motor now compared to last year or the year before?

no i'm not burning any oil, no new sub woofers or rims... would it make a difference that my tires are super bald now? oh and ummmmm i hella let myself go and gained like 20 pounds since last year i'm going to the gym to try and drop that weight though lol i have 26,4xx miles on it right now and last year had about 14,000 miles on it.... i'm thinking maybe since i drive it hard a lot, maybe the injectors could have gotten a little dirty?

[darkmessenger]

Canadian units.

I get about 800-825 kms per tank. (I once filled up with like 20-30 kms left on the range with the odometer reading i've already driven about 800 kms since my last fill up)The tank is like 70 litres825/70 = 11.70 litres/ km = 27.7 mpg

Thats doing 99% highway driving. Thats as good as its ever been for me.

wow really? I usually get about 600KM per thank.. and my mileage is about 10.8 L/100KM, but I do mostly city driving. Man, we need more highway here at Vancouver.

[BlackMamba08]

27MPG? i think that's actually pretty good...once i swapped out my stock wheels, i've been no where near that. i'm closer to 22MPG...

[Hussain]

i mean, if i were to not reset my gauge for a while it would dramatically drop (it dropped to 19.5 MPG now) but i mean, if you set the cruise control and just cruise the whole time with no up hill driving, you're supposed to get like 30+ MPG

[adidas2go]

I get like 11 mpg. Be happy A lot of people used to read the mpg and mph readouts wrong, which is what you may have been doing.

[BigDankCloud]

As far as the injectors thing goes, I would think that does have something to do with it. I recently had Nissan do the whole injectors cleaning service, and the engine performs so much better. It seems that I rev quite a bit quicker now, and that its done my average mpg has raised from about 21.7 to 22.9.

Don't however do this. The stealership f'd me and told me one price initially and then when i came back there was a "misunderstanding" and i actually owed them 3x what they said initially for all the service i got done.

Instead, i'd be buying the injector cleaner bottles from autozone (make sure it is compatible with the seals in your car first, most are) and using them more frequently.

[losenone]

As far as the injectors thing goes, I would think that does have something to do with it. I recently had Nissan do the whole injectors cleaning service, and the engine performs so much better. It seems that I rev quite a bit quicker now, and that its done my average mpg has raised from about 21.7 to 22.9.

Don't however do this. The stealership f'd me and told me one price initially and then when i came back there was a "misunderstanding" and i actually owed them 3x what they said initially for all the service i got done.

Instead, i'd be buying the injector cleaner bottles from autozone (make sure it is compatible with the seals in your car first, most are) and using them more frequently.

Its called Techron, works wonders. Just make sure you dont use it too often, it dries out the seals if you do.

I would also recommend cleaning out the MAF.

[IBCoupe]

In a 3.5? I'm struggling to get my car to do 24MPG, and that's 90% highway (at 70-85mph, granted, but an easy acceleration to that speed).

Now you've got me worried.

[Beak]

u rag your car out tooo much.

[BigDankCloud]

Its called Techron, works wonders. Just make sure you dont use it too often, it dries out the seals if you do.

I would also recommend cleaning out the MAF.

Yeah,I'm going to start remembering to buy a bottle of techron when i do my oil changes.

[Beak]

replace your pcv valve... the spring is prolly worn out from agressive driving. the dealer might tell you that you dont need to replace it, but they are dumb. basicly when you punch it the sping opens all the way and when ur in at a red light or idel its closed. flooring it all the time will wear it out. uve had the coupe for around 2 years now i assume. change it and watch the mpg go up, not to mention cleaner revs, its costs like 12 bucks.

[Beak]

i cleaned mine over the weekend and saw an improvment, got mine ordered

[mpbclutch33]

I don't even think it is possible to get 32-35mpg in the 3.5L. I have taken several long trips, and the most I could muster was 28.1 mpg for the trip. In mixed driving, I average 23.7 mpg.

[Hussain]

just leave it in 6th gear and use cruise control.... you have the 6 speed so you should be getting even better MPG. i remember some 3.5se sedans saying they just put it in 6th and use cruise control and get like 35 MPG

[Hussain]

PCV valve? whats that?

[Beak]

its a valve right behind our headers. its what lets the engine pressure breath. a bad valve can but a lot of pressure on your rings. they should be changed every 15 k. and do not listen to anyone who says other wise. i know you drive agressive and im sure your engine is begging for it.

[Hussain]

you said it cost like $12? where can i buy it at? got any pics or a quick write up?

[mpbclutch33]

http://www.courtesyparts.com/1....html

[wade001]

Its called Techron, works wonders. Just make sure you dont use it too often, it dries out the seals if you do.

I would also recommend cleaning out the MAF.

i agree with you on not using that injector cleaner to often, it works by removing carbon and fuel varnish, but then again, the brushes on your fuel pump are carbon as well i believe (was told this by my fuels teacher at school). cleans everything in the engine but rust and really helps but i dont think it is needed at 26k. unless the fuel you get is bad.

[Beak]

ill do a write up once when mine come in.

[txcoupe]

would it make a difference that my tires are super bald now?

Yes it would, and does, make a difference. I would think that this would be the primary cause of your loss of MPG.

I've found that when you replace bald tires with brand new tires, It's like a brand new car again. All of a sudden it rides smooth, not nearly as much road noise and handles like the day you bought it.

Everyone else is correct also. Clean the injectors, replace the PCV, and reset the ECU. You might also look into changing the fuel filter. I haven't done it on mine, so I don't know how easy or difficult it is to change. The MAF suggestion is good too, but you gotta be ULTRA carefull when messing with that. If it was me, that would be the last thing I'd mess with, and only if I had to.

Are you running an aftermarket intake? When was the last time the airfilter was cleaned/replaced? That can make a hell-a impact on the MPG.

[Hussain]

ya i need to get some new tires.... i have the stock intake and replaced the air filter 10k miles ago and will replace it real soon (they say every 15k miles)... i'm thinking the biggest thing is the tires... i reset my MPG monitor and have been doing city driving and every once in a while having some fun with it and it says i'm averaging 12.9 MPG.

[Beak]

new tires wont make your engine feel like a new car. but a $12 pcv valve will

[EzeebMOS3]

My 3.5 CVT gets around 20MPG average... So props to you guys above 24/25