so i have a 03 auto and within the past year the cars performance has just dropped. i need a new suspension and probably a full exhaust and probably headers.. when i fill up on average i get 165 miles for the full tank.. can anyone explain this gas mileage drop? im guessing to fix everything its guna run me about 3-4g.. should i dump the max and just use the money on a down payment??

 

New air filter
New plugs if original
Clean or replace MAF
Use the correct grade of gas
Have the knock sensor checked

That is **** poor mileage man. I have half a tank left and I have over 165 miles on it as of tonight.

I wouldn't dump the car unless its actually giving you problems. Most suspension parts do get tired, but things like struts do not need replacing instantly, they can go blown for a while, if you need to save some $ to swap them.

Nothing here sounds too serious. my 02 is in great shape, needs nothing, and gets better mileage, but of course, I did all the things I suggested at the beginning of my post.

 

i only use 93 octane.. i have 83.5k miles on it.. car just feels unreliable and about to fall apart on me lol

 

Also take a look at the throttle body and see if there is any build up. I get that mpg on my wagon lol. My Max right now I push it hard usually, and still average roughly 300-325. Thing's I've done to help my mpg was: cleaning tb, maf, and K&N Filter. New knock sensor, NGK plugs I also used fuel injector cleaner.

 

I'd take it to a mechanic and have it checked out. Find out what the cost will be to bring the performance back and replace worn suspension components. Then divide that by 12 and see if it exceeds what you'd expect in monthly payments if you bought something else. Our cars can last a really long time if well cared for. I hit 174,000 a week ago and all it took was replacing the precats with used, low mileage ones and swapping out the main cat with a test pipe to bring the performance back.

 

What craig SE said + w/e you can afford for an exhaust.

Personally, I'd do/replace everything craig mentioned, get a Y pipe and hollow the cats. Unless there's some other weird issue, there's no reason you won't be running back in tip top shape.

With any decent mileage you can bet the cats (aka engine killers) are clogging or already clogged, MAF is worn out and plugs are super fouled. KS is potentially bad (easy test).

Also, you should change the tranny fluid asap if it hasn't been done before (drain and fill only). I'd throw in synthetic and not worry about it for a long time.

I bought mine (03 6 spd) with 154k and now have almost 169k. It does have boltons so the exhaust isn't an issue, but I couldn't tell that anything has been replaced on it except for the aftermarket stuff.
And you can bet that if something was going to fail, it will with me driving. It's redlined and WOT dozens of times per day. She never gets a rest

 

stay true to the maximas man. keep it. you'll love it in the end

 

+1 full agreement

 

make sure if you clean that throttle body like someone suggested on here you take it off the upper intake manifold, don't jar it and do not move it with your fingers in fact don't move it at all! this could cost you even more money and steer you completely away from your maxima, i had **** poor gas mileage...not as bad as yours but it was the maf, do the 2001 maf with the resistor swap(cheaper and stronger) and hollow out the cats like someone else suggested(free) also Jime helped me by putting a resistor in the knock sensor i forgot what the rating was on the resistor but you could pm him i'm sure he'd tell you, that eliminated my knock sensor being the problem costed me like a dollar for a 10 pack of resistors from radio shack. plugs shouldn't be to expensive, if the coil packs are sh*tty, that can get pricey, but talk to dave brunette for a price on those. over all you're looking @ about 150-600 bucks in parts depending if your coil packs are crap. The hollowing out the cats is just going to tell you if you should go with the new headers and high flow cat. but i agree suspension can wait...get the motor going first. I don't know how handy you are with cars but if you can do this on your own it's going to save you a ton, the write ups on here are awesome.

 

thanks guys for the quick response.. im going to bring my car to a mechanic by me and hopefully he has some good news for me.. im hoping not to dump more into the car then what its worth.. im pretty sure my exhaust is shot because a few years ago my mother was driving my car and got hit from behind by a drunk driver.. bumper was fixed but the exhaust remained untouched.. after that accident im pretty sure i had a hole in the exhaust somewhere because around 1800-2000 rpms id get this really bad growl .. if i need to change everything im not sure its worth putting it into the car.. i was looking at the 7th gen maxs, a 370z , and dont laugh but yes a wolfsberg jetta.. i know that mite sound gay but that jetta has some *****.. vw knows what they are doing. ill keep the thread updated when i find out more.. thanks every1

 

TUNEEE UPPPPPPPP, or a hole in ur gas tank

 

yea, go get it checked out, gas mileage is easily fixed with the performance parts you wanted to get, hopefully you dont still have the stock filter for 83K miles and be crying about MPG...

 

The only reason I let my max go was because the cost to maintain it was more then a monthly car payment. Just surprise repair month after month. My AC went out, which is way to much to replace. Constant engine light, which made it tough to pass inspection every year although I managed to do it. Poor gas mileage, missfires, going to need new struts, body rust, adding oil in between each oil change. I had 215k on mine but even my step father agreed (first owner of the car, I bought it from him when graduated) there was just an inherent problem with this specific car that no dealship or mechanic could ever get right. But I did love every mile that I drove it.

 

maybe for you lol... gettin a payment on a maxima was $400 a month for me, i definately dont spend that much a month on mines now

 

OP, how many miles on your Maxima?

 

Post #3........83.5k. Not bad mileage at all.

 

What I meant was I own the max, it was paid off. But I was investing more money into repairs (not upgrades) then it would cost for me to just buy another car and take on a monthly payment.

 

Besides the exhaust (b/c of rust) and suspension it's all DIY
Shouldn't cost much at all, then.

Odds are that right now it's just MAF and/or KS.

 

Is it actually possible that the cat and pre-cats are really THAT clogged on the OP's car? It only has 83.5K miles on it! Mine must be gettin' bad at 127K... I suspect they're pretty clogged. I bought my Maxima at about 80K, so I don't really know any different. Man, I can't wait for my new headers/fastcat/catback to ship... Imma see some sweet gains

**Edit** - Oh, and keep the max

 

is my maxima just special? i range from 28to32 in the summer, and 24to27 in the winter

 

The answer depends on personal priorities. Money might seem like the deciding factor, but it really isn't. The money you spend on repairs and upgrades vs. the money you spend on a new ride... at the end of the day it's pretty much the same thing.

The real deciding factor is time, not money. If you keep your ride, you will be investing more of your time in it. For most of us here, that's the whole point, and what makes owning a 5th gen such a rewarding hobby.

If you don't want to invest the time, move on and no regrets.

 

If you are going by the trip computer, subtract about 3-4 from your numbers to get your real mileage. Mileage also depends on your driving habits. A lot of freeway or living in an area that doesn't have stop light after stop light yields better mileage assuming you aren't constantly romping on it.

 

Hope that subtracting 3-4 mpg isn't true...my trip comp currently reads 15.7 mpgs. It actually increased from 14.6 mpgs when I changed my plugs and knock sensor.

I'm thinking the OP needs to clean his MAF and TB. Seems a bit early for his cats to get clogged.

 

Sorry to be the bearer of bad news, but the trip computors are off by 10% - 14%.

 

^ all these guys are right.

clean tb (free if u have a ciool mechanic would still take it off and let u tooth brush it or w/e clean it with some type of electrical part cleaner to get the gunk off/dirt off)
new spark plugs (like $20 bux or less)
clean or replace maf ($6-$90 depending on what u do)
change/clean or remove cats get headers and a nice straight pipe (like 300 bux maybe?)
knock sensor how much is that ?


by looking at this i wouldnt spend more then 500 and its a 1 time thing. then u can save ur money for other aspects of your life. surely your car isnt the most important thing going on in your life is it ?

and just a light tuneup (prolly like another 120 bux for new air filter, incabin filter,pcv valve, and fluids swapped.. whatever a tuneup typically involves) and i garentee itll be all back. save ur money bro. monthly payments are a b*tch i have a 2010 coupe and a 00 maxima and i am forced to pay for the 2010 everymonth but i want her and wont give her up lol. but the max i just works and i use her alot and fix her when i can or really need to. i also need a tuneup soon and some headers but i figure ill do that and be done with the money spent on the max besides gas n cand the usual stuff like car washes, etc..

at the end of the day cars are cars and they ae other things to worry about but i do share your sorrow, as a man. i do love my cars bro. lol.

 

thanks for everything guys.. but if im guna invest time into this car i wana do it right.. im looking at numbers and hopefully i can spend about 4-5g on the car to fix it right... everything is stock right now so if im guna do it im guna go after market... my thoughts on suspension was tokico illumina stuts with h+r springs.. i live in ny and wondering with the pothole being on steriods is this to much of an aggressive drop.. im hoping for exhaust i can get my hands on cattman headers and full exhaust.. i dont see a point in puttin stock on if i have to spend the money... im gussing with those two items im guna be dropping about 2g.. if im puttin all this is the car guna be running to lean if i can get the gas mileage under control??

 

Like i said before, that sounds like way to much i think it will be less, I don't know if you have access to tools, but some of the write-ups on here are great, or download the FSM for your car and follow directions, you'd save a ton of money, my cattman headers were 700 bucks and you can get a full exhaust catback exhaust for 169 http://www.custommaxima.com/product/...m/Default.aspx and a high flow cat for 50 http://www.custommaxima.com/product/...r/Default.aspx if anything your car will probably be running rich after all of that i know mine was. get a Technosquare reflash around 500

 

keep it if i was u i would keep it the mileage is not bad to

 

About the cats clogging...mine toasted the engine at 75k.

I think I'm more of an exception at well under 100k, but we do know that running rich will destroy them in short order.