matrix11229

I cleaned throttle body a few weeks ago, and since then it idles at ~1400 (and 1000 when I shift to D) when the engine is cold, and it takes around 10 minutes when the car sits still until it drops to 900 rpm which is the idle I had before. But I never wait so long , so I start driving and after 5 minutes I check the idle and it's normal (900).
Also it takes a bit longer to start the engine than it was before.

I used Gumout throttle body cleaner. I cleaned it with a toothbrush and after that I opened the butterfly plate and cleaned the inside behind it.

After I cleaned it, the car doesn't vibrate as much as it used to be when it sits still with shifter on D. But I still feel some vibration even with warmed engine.

1. Did anyone have this issue ?

2. I wanna adjust the idle speed but I don't know where the stopping screw located on the throttle body. Does anyone has the picture of it ?

3. According to the stickies the idle should be around 650-700. What's your idle ? what rpm do you have when you shift to D ?

4. I have terrible gas mileage around 13-14 mpg in the city. I replaced the knock sensor , O2 sensors , fuel and air filter . Do you think I have to replace the spark plugs and pcv? My mechanic took one of the plugs out and said it's still good (it's platinum). I bought this car a few months ago, and the previous owner drove 60000 miles on her (now it's 189000) , and he said he didn't replace anything.

ardika

iTrader: (3)

High idle after cleaning throttle body is normal. I have cleaned mine 4 times and it always give you a high idle. However, my normal idle is 800 rpm (shifter in N or P) and drops to 650-700 in D (with brake pedal depressed).

Mine gives me about 24-30 mpg though, and I am definitely not near the 14 mpg mark. Gas mileage depends on a lot of things, most likely the driver's driving habit. When I had my Maxima in NYC, it only gives me about 18 mpg and I was trying to be prudent.....

f550maranello2

iTrader: (2)

lol there is ur answer.. replace the fuel filter the spark plugs and pcv valve..

shadyonedeath

iTrader: (10)

Idle is when you turn it on and dont press the gas right?

If it is...then mine idles at a lil bit over 1000


This explain my ****ty mpg?

nguyen925

idle is basically when ever you completely stop at a red light or if your parked. question for you, do you have the car shifting above 3-4 RPM's? cause if you are, your bound to suffer in gas mileage...i get about 22-23 city =/

shadyonedeath

iTrader: (10)

mine shifts at about 3-4.

but ya, my idle is a lil over 1000

wetzelman1

iTrader: (2)

i'm going to watch this because this sounds exactly like the problem I'm having with my car. I've done everything maintenance wise besides change the fuel filter (becuase I misplaced my 300zx one) and I still get about 14 mpg.

Brudda Bob

iTrader: (3)

Regarding your poor gas mileage..I was having similiar city mileage and was on the verge of disposing of my car until
...I replaced the MAF sensor (used), PCV and Coolant Temp. Sensor (Nissan) and replaced the battery lugs with generic ones.

Prior to this I replaced the:
Plugs with NGK OEM rec. specs.( saw that the old ones were perfect upon removal also NGK OEM specs.)
Nissan Fuel filter , Air Filter and PCV
Denso rear O2 sensor
Cleaned throttle body
Used several bottles or Techtron injection cleaner to no avail

There was NO IMPROVEMENT in the gas mileage with ALL of this.

However, with the recent replacements the car is an absolute blast to drive now. It's fast, very fast ,super fast and the mileage is way way better.It can easily do 110+ mph and you wouldnt even know and it seems to just wanna go more.

I'm not a mechanic and dont know which of the replaced components helped the most but I would highly recommend replacing the PCV and the Coolant temp. sensor (not that difficult to replace) with Nissan parts (bout $35.00 total ) and see if there is an improvement. If that STILL doesnt help I would try the MAF (see if you can have swap someones) since its about $400.00 at the dealer.

Lastly, I was told by a Nissan tech. that his experience with Nissans that has over 60K miles is to ALWAYS replace the O2 sensors,Coolant temp .Sensor,PCV (Nissan ONLY) alonG with the regular tuneup parts.

Hope the information helps and good luck. "I can feel your pain everytime you need to refill the tank". "Good luck"


One.

nikk1973

i'm going crazy wut my max....i change out the pulley and the alternator ....and when i finish with that my idle act up too....the rpm goes up and down..? and when in drive it hesatating...the hesitation comes and goes ...i just don't understand why...?...???? did i do sumtin wrong....or sumtin when out????? pleas help..xxxxxxu

matrix11229

Thanks Bro !

Good to hear that someone had this mileage problem solved.

I'm gonna replace the pcv and coolant temp sensor and see what happens.

PCV from Autozone is ok too ?

Your MAF was throwing a code ? How did you know it was bad ?

What was the problem with your battery lugs ? You couldn't just clean them ?

Brudda Bob

iTrader: (3)

PCV from Autozone??? I CANT say whether a 3rd party vendor supplied part is worse, the same or better than OEM. I WOULDNT purchase one from anywhere besides the dealer because the price difference isnt significant (about $2.00-$3.00 diff.). I ALWAYS purchase dealer parts in such circumstances and thats MY personal preference.

The MAF (even though there wasnt a code) and coolant temp. sensor were replaced solely based on the recommendation of my Nissan tech.friend. He explained that sometimes these parts DO NOT trigger a code but they DONT work as effectively as they should. It will throw a code when it's really bad. The mechanic also told me it would be a problem if the outlet of the muffler was smaller than OEM spec. but he doubted that was my case.
I also researched the stickies (tons of info. in the archives and well worth the subscription) and Symptom Matrix Chart in the FSM (wealth of info.) pgs.87 and 88)


One of the battery lugs could have been cleaned but the other was cracked. I replaced it because it just wasnt costly. Also, in the FSM it states that if there is a problematic main power supply and poor grounding that it can be a cause of excessive gas consumption. You would be amazed at the problems a poor power supply can lead to (based on the FSM)

The FSM is truly an information overload document. It has a solution for almost anything and then some. Problem is (for me) is that it's time consuming and involves too much reading. Check pgs. 87 and 88 (Symptom Matrix chart) if you have access to the FSM. I dont know how to insert an attachment here otherwise I would post it.

PCV was purchased sometime ago from Courtesy Nissan (dont recall the price) and the Coolant temp. sensor cost me $20.00 from my friend who recieves a 20% discount from Nissan.

Bro, my car flies (I was right under a 350Z this weekend and barely glanced at my speedometer to see it was at 120 and the car was STILL pulling hard. I'm merely pointing out an observation and not starting a "race"thread) It's the FASTEST I have EVER driven the car and didnt even realize what speed I was doing.That's because it's so much smoother, powerful and responsive. The best part is that the gas gauge barely moved.

SmurfLeech

This is exactly what happend to me. Bought my Maxima and then cleaned out the throttle body. It used to idle at 900 and when I start it it gets up to 1500 and then decreases to 1k (after some time).

Changing the air filter, fuel filter, spark plugs, and some other small maintenance things haven't helped.

Recently my car gave me a check engine light and it appears my post cat. 02 sensor has a problem (not surprised, my car has over 90k miles). So, I'll change that, the PCV, and the coolant temp. sensor. If that helps the idle, I'll post again.

happyscrappy

you can get the FSM in PDF format at http://www.phatg20.net. it's totally chock full of good info. go get it.

Maxgig

iTrader: (5)

I'm assuming, (since none of you stated otherwise), that you all have automatics. I have a 5 speed and I know my car should be faster than it is, my gas mileage isn't terrible but it isn't great either. And, since I still have the original ks I am seriously considering replacing it. But don't want to get taken by the dealership, (I don't have the patience or small enough hands to fish the extensions into the crevass to get to it). I've replaced everything else but the ks. I'll look into some of your suggestions, thanks.

matrix11229

I just picked up the PCV and Coolant temp sensor at the stealership , they charged me $ 45 .

Thanks for the "FSM Manual" link - HappyScrappy

I downloaded the FSM manual, it has a lot of useful info.

matrix11229

Those are the pics of the PCV and Coolant Temperature Sensor.
Did I get the correct ones ?

nitink

I am facing the same problem, whatever i have read on other places you need to clean IACV & IAA very thoroughly.
For ECTS you can try cleaning it first , its not something that goes bad easily, but your coolant can get contaminated and decrease its efficency, so changing coolant would be better than changing sensor.

I will try these things on my car on Saturday and let you guys know.

matrix11229

I hope I will change my coolant this weekend too. There is a nice writeup at motorvate.ca .Where do you get rid of the old fluid ? I guess it's a poison

Brudda Bob

iTrader: (3)

Looks like mine and assuming the part numbers are correct youre good to go. Like someone else suggested it's a good idea to change your coolant and also clean the IACV. I'll change mine and also replace the thermostat whenever time permits.

$45.00 is a little too much for me just be sure to always "shop" around. The prices from the dealers arent always the same. I've found Star Nissan in Bayridge Queens to have better prices than most of the other dealers in the surrounding areas.

Are you doing the job yourself? The temp. sen. is a 19" deep socket. Hand tighten it first to ensure it's not cross threaded.

The symptom matrix chart in the FSM is on page 87-88 of the EC section.

Good luck!

matrix11229

Thanks Bro

I'm gonna replace the parts on Saturday.
I don't have a deep socket, may be an open end wrench will fit there ?
did you use an extension with the 19 deep socket ?
what's your gas mileage now? and % city % highway driving ?

Brudda Bob

iTrader: (3)

I used an open end socket but needed to remove a portion of the MAF plastic thats bolted onto the radiator support.

I havent done any calculations regarding the current mileage because I have 2 other cars which I've been using. I KNOW the mileage has improved because I've visited the same places I previously did and used less gas. Also, I have driven the car the hardest it has ever been driven and the gauge barely moved. Previously I would "baby" the car just to save gas and the mileage was still ridiculous.

I'm lending the car to someone this weekend who will be driving to Toronto so I'll have them log the mileage/gas consumption.

If you dont see an improvement I suggest you peruse that FSM Symptom Matrix Chart and go with the simplest/easiest recommendations.


G.Luck

matrix11229

Finally I replaced the spark plugs with Bosch Platinum 2 , replaced PCV and coolant fluid. Didn't replace the coolant temp sensor yet. And I added Lucas injector cleaner.

I feel some improvement in performance but now I get some vibration when the car idles. I doesn't vibrate all the time , approximately 30 sec in every minute.