thefed

Hey guys, thanx for all the info you offer, it's proven invaluable(im a noob). Here's the deal. I bought a 98 gxe auto with 69k on it recently. I was getting a measly 16.5 mpg. SO, after reading my STICKYS I:

Cleaned throttle body
Cleaned IACV
Changed plugs to NGK coppers
Changed Air Filter
Did a "mini" tranny flush, 3 drain n fills(for tranny issues)
Changed oil (dino oil )


After that, my mileage readings were 18.8, then 22 mpg.
My most recent tho was around 17 again

SO I pulled code 0403 which sends me to the TPS. Could the TPS cause shi**y mileage? I DID have a case of stalling out on startup before i cleaned TB and IACV (that's why i did it!), but thats been okay.

Other "symptoms" ,if u will, are randomly sluggish acceleration, a hard 1-2 shift, a hard 2-1 downshift on occasion.

Does this sound like a shot TPS or one in need of some dealer love?

I dont have a multimeter to help diagnose, but where could i get one?autozone or hardware store i wonder?

I've been driving rather mildly, under 3500 rpms, 1/2 hiway, 1/2 local,wot maybe 1 time every 2-3 trips, really been takin it easy,running 92 or 93.

Anyway, thanks 4 the input, I appreciate all ur guys help. Hopefully i covered enuff bases not to get flamed on my 1st post lol

thefed

anyone know? im sure SOMEONE can offer some info

Akumachan

iTrader: (12)

wow, 17 mpg while driving so granny like? thats pretty bad, somethings gotta be wrong, but uhh... i dont even know what the TPS is...

illmortal

For your spark plugs you should stick to Iridium.

MDeezy

iTrader: (27)

no need or iridium unless he's making some serious power and need that strong spark, if he's NA and still basically stock, it will do more harm than good.

MDeezy

iTrader: (27)

you read the stickies ( ) so you wont get flammed.

I dont think the TPS can cause bad gas milage, but you have a code for it, get it fixed and see if that helps, only other thing that could cause such bad gas milage is is o2 sensor shot, or KS, check codes again and see if they are hidding in the ecu

illmortal

oooo I believe the manual of the Infiniti I30 says to use Iridium.. I'll check it over again to check that out.

I30tMikeD

iTrader: (8)

1. There is no reason to use Iridium plugs. NGK coppers are just fine. The plugs are not the problem if you indeed replaced them with either NGK coppers or plats.

2. Not 100% sure if the TPS would cause a fuel mileage problem. What I did not see listed was a new fuel filter. I would do that as well. How the TPS sensor works in conjuction with our ECU it could cause fuel mileage problems, I just don't know that for sure. If your getting a code for it then check it with a multimeter. I would buy a Haynes manual from your local auto parts store. 4th gen maxima's have two different TPS set ups. Either just the TPS or a TPS and WOT sensor and the process for checking them is a bit different. It is explained in detail in the Haynes. You are gonna want to check the voltage of the TPS to make sure the voltage rises correctly between closed and open throttle.

thefed

Thanks 4 the input guys. no, i did not do the fuel filter as i saw it looks kinda fresh and is a WIX filter, not oem. i was under the impression it was a 60k maintainence item to replace, and i saw newer plugs when i did them soooo, i assumed it was newer. Is 60 k right for fuel filter, or is it 30k? cant remember, gotta check the manual.

I did check the ECU again after driving a bit(and resetting) and I get the TPS code again...no KS, or O2. Im at a loss! My tire pressure is good...just checked that.

I WILL replace the fuel filter, and try to get a multimeter (but where do I get one!?!?) and how much are they. I could just get a new TPS for 60.00 and KNOW its good, but it is kinda wasteful. On the other hand, the code does say TPS.

17 -18 mpg is gonna kill me! lol I was hopin for 22 ish. I just tried a new gas station this fill up, I'll see abt it.

I called NISSAN stealership, they said TPS code does no neccessarily mean TPS?!?! Said it could be a MAF, and those codes often lead to other codes.

Any more help would be great. Thanks guys

I30tMikeD

iTrader: (8)

If you plan on installing a new TPS you will need a multimeter to calibrate it anyhow so you need one no matter what. A decent multimeter will cost you $20 or so at a basic hardware store like HomeDepot or Lowes

If your MAF is bad you will get stumbling from the motor and the car will not run right. I would look at the TPS first since that is the code your getting.

Not to insult you, but are you sure your checking the mileage the correct way? I don't get much better than 19-20 mpg all city driving with my 5spd

thefed

yeah, i know how to check my mpg. fillerup,set trip,fillerup,divide miles by gallons.same pump,same gas. maybe my expectations are too high. but how are these guys getting 23-25 all around miles? im at 17 1/2 hiway 1/2 city.some claim 30!! i got 22mpg and that was 80% hiway!!! something doesnt add up.

I will buy a multimeter, read the write ups on it, and try to adjust it. What do u all figure the stealer would charge for adjusting/replacing a tps, if i supply part?

thanks again

minsbang

The stealers will charge you in the ball park of $60-$70/hr in labor. And you'll be lucky if they agree to install the parts that you bring in. Call the service department before you walk in.

michaelnyden

iTrader: (15)

I get anywhere around 17 mpg 99-100% city and that is in LA which is mostly stop and go traffic which kills gas mileage...plus I do drive semi-aggressive occasionally (here-and-there) but I am a stick with all bolt ons....I would say try getting the gas mileage increasing mods like flywheel, upd, exhaust, intake....but in the end, you will just be using more gas cause your car would be that much faster so you will constantly be on the pedal more! I know that's how it was in my case, my mpg stayed consistent as I was getting better mileage from those mods, but using more "go-fast" pedal....also check your tire pressure....won't make a gigantic difference in MPG...but raise them up a little to get better mileage...

owais

iTrader: (20)

Are you sure you read the codes properly? That sounds like knock sensor which is 0304 if I remember correctly. Maybe you just flipped the short blinks with the long blinks by accident.

goodhead

iTrader: (4)

hey bro i did flip the codes like what owais is saying i thought i had a tps sensor problem, found a fix on one of the other maxima info sites and was ready to do the fix decided to check the code again and i indeed read it wrong it was a knock sensor code. jsut double check to make sure you didnt make the same mistake

flthere

iTrader: (2)

Any idea what causes this random sluggish acceleration and a hard 1-2 and 2-1 shifts !?! I probably am experiencing this ... I have new air filter and fuel filter. Maybe I need to clean TB though ... haven't done this yet ...

And I had done the full flush-n-fill of Auto Tx fluid, still the hard shifting persists

thefed

yeah, it 0403 for sure....i double checked.

Anyone know if this "hidden" tps code would make me fail the ohio emissions check? they use an OBDII scan to test.

MDeezy

iTrader: (27)

I dont know if Ohio emission is like Georgia, but if we have a cel on, or hidden codes we automatically fail emissions, we cant have any cel's stored or anything.

goodhead

iTrader: (4)

i dont htink the tps code is hidden jsut the knock sensor code is hidden and yes it will fail emmisions

thefed

AAHHHHHHH!i am an a**hole! I looked at the code 3 times yesterday, kept getting 0403. Now, after the last post, i go look again, and i realize i had the long pulses/short pulses confused. SOOOOOOO. KS! 0304

Question: as this is such a common code, will I still fail emissions?

BTW thankyou all for your input. Feel free to flame as needed.

MDeezy

iTrader: (27)

why thank you. . .


you F***kin noob, had us trying to help you all this time, but you messed it up!!

is there a code for noob who cant count?





just messing with you, glad you found out it was KS, your payback for bad counting will be having to fix it, and I'm sure your car will scrape you up good!

I30tMikeD

iTrader: (8)

Knock sensor makes much more sense. Buy one on ebay, an online dealership or Dave B the parts guy at SouthPoint Nissan in Texas. Should cost $60-$70 new. Install it yourself. There is a how to in the stickies

thefed

WILL I FAIL EMISSIONS TEST THO WITH A CRAPPED OUT KS? IM GOING TOMORROW AM. I THINK IF I FAIL IT SHOULD BE COVERED BY MY HALF-A** WARRANTY I GOT, 30DAYS/1000MI FROM THE DEALER.aNYONE FAIL E-CHECK FOR HIDDEN ES CODE?

thekenone

i live in ohio, did they actuall hook up a scanner to the computer. i know that if the light is on you automatically fail in ohio but i didn't think the checked the computer. i passed my e check the last time with both bad 02 sensors and bad ks.

1MAX2NV

iTrader: (5)

clear the code and check again. TPS is not that hard to replace. It's alittle tricky on the adjustment part though.

pavelsmax

iTrader: (12)

i'm in jersey and they didn't even scan my ecu in 2003 when i had mine inspected... my cel just came on tho so i''ll have to take care of that before inspection in a few months

izzydig

If you read Nissan's say on hard shifting, it can be caused by a mal-adjusted or bad TPS. I'd adjust it. Hard shifting can be common, but atleast give ur car free MPG at the expense of $5-10 multimeter.

Now with your dyslexic readings (as opposed to a KS), I wouldn't be sure, but just adjust the TPS anyway. With 4th gens getting older and older...TPS should be a common tune-up item.

goodhead

iTrader: (4)

lol told you, anyways if tis a odb-II scan you will fail, how many times do i have to say it???

thefed

wELL, I TOOK IT, RE*** THE ECU 1 MILE AWAY, AND PASSED. WHY?

Cuz the computer wasnt ready and wouldnt give them the info they wanted, so they did an old school treadmill test. Still gonna fix it, I hear it'll bump up my mileage and give the engine a nice little boost. Thanx guys

MDeezy

iTrader: (27)

u lucky bastard

I thought of doing this when I had codes to get my emissions done, but it was just the thermostat, and coolant temp sensor, so no biggy.

you slipped thru the crack, but your still going to get bad gas milage and sh itty almost civic like performance, get that KS fixed.

illmortal

Damn thank goodness I live in S.Florida... no emissions test done here, but it's also a good idea to get the CEL resolved

Morgan Reitz

I had a Low TPS Circuit CEL, and I was getting a 11.5:1 AFR on my wideband. I readjusted the misaligned sensor, and now I'm getting stoich (14.7:1). Test the sensor voltages, and if they seem off, see if there's anything you can do to fix it, and if they're inconsistent, replace the sensor.

PH98I30

Morgan, this is a 12 y/o thread. Commenting on it probably doesn't do much good I am sure the OP solved his problem by now.

max ride 41

iTrader: (4)

wow, so many years and soo many noobz....