# 84 300zx idles but dies when i give it gas



## Aphterskulspeshl (Dec 22, 2004)

Hi everyone i am a boke 22 year old that bought as used car and it ran fine for a while but the one day i went to start it and it would start and idle fine but when i went to give it gas it died immediately. I am not sure what is wrong so i was hoping someone could maybe tell me what to looke at cuz my dad is stumped also. we unhooked the little computer plug that is on the little box rigth in front on the air flow tube..(sorry for the use of words but i am not a car person) and it would idle and then we could give it gas but it would sputter alot and die at 2k rpms. if anyone has any kind of help it would be much appreciated thanks.


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## asleepz (Feb 24, 2004)

I would check the timing and do a tune up (fuel filter, air filter, plugs, wires.)

And that little thing you unplugged was your Mass Air Flow sensor and you need it for it to run properly.


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## Zen31ZR (Mar 24, 2004)

Stumps me as to why you'd go unplugging something that you don't know the operation of. And then complain when the car doesn't run right immediately afterwards.  Let that be a lesson to you. And learn something about cars before you start messing around. Fortunately you picked a fairly easy car to learn about, get a Haynes manual and download the factory FSM which I have links to in the stickys at the top of this page.


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## asleepz (Feb 24, 2004)

I think he unhooked it after the problem arose but still. Don't unplug anything you don't know about. It's not real smart.


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## Spongerider (Nov 18, 2002)

Aphterskulspeshl said:


> Hi everyone i am a boke 22 year old that bought as used car and it ran fine for a while but the one day i went to start it and it would start and idle fine but when i went to give it gas it died immediately. I am not sure what is wrong so i was hoping someone could maybe tell me what to looke at cuz my dad is stumped also. we unhooked the little computer plug that is on the little box rigth in front on the air flow tube..(sorry for the use of words but i am not a car person) and it would idle and then we could give it gas but it would sputter alot and die at 2k rpms. if anyone has any kind of help it would be much appreciated thanks.


Is your check engine light on?


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## asleepz (Feb 24, 2004)

Spongerider said:


> Is your check engine light on?



Can we say pre-OBD I? We don't have one.


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## Spongerider (Nov 18, 2002)

SKD_Tech said:


> Can we say pre-OBD I? We don't have one.


Well there went my wasted $.02 :jawdrop:


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## asleepz (Feb 24, 2004)

Spongerider said:


> Well there went my wasted $.02 :jawdrop:


Awww it's alright....


This time


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## Zen31ZR (Mar 24, 2004)

Dang. Spongey got pwned and I wasn't even here for it? :thumbdwn:


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## asleepz (Feb 24, 2004)

[email protected] said:


> Dang. Spongey got pwned and I wasn't even here for it? :thumbdwn:



Nope you missed out


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## JAMESZ (Mar 12, 2004)

[email protected] said:


> Dang. Spongey got pwned and I wasn't even here for it? :thumbdwn:


I PWN him all the time.

As for your issue I would think it is either the fuel filter or the MAF (Mass Air Flow sensor the thing you unplugged). Just replace those two and see if that fixes the problem.


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## Aphterskulspeshl (Dec 22, 2004)

[email protected] said:


> Stumps me as to why you'd go unplugging something that you don't know the operation of. And then complain when the car doesn't run right immediately afterwards.  Let that be a lesson to you. And learn something about cars before you start messing around. Fortunately you picked a fairly easy car to learn about, get a Haynes manual and download the factory FSM which I have links to in the stickys at the top of this page.


well the car had the problem first before we unplugged it my dad is a mechanic but not good with computer really a back yard mechanic if you may say and he knew it had to do witht that part cuz of the build up of carbon on the plugz so we unplugged it to see if it made a diff. cuz it wan't working right anyways. i just asked for help i didn't ask to be criticized thanks you though for your input


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## Aphterskulspeshl (Dec 22, 2004)

SKD_Tech said:


> I would check the timing and do a tune up (fuel filter, air filter, plugs, wires.)
> 
> And that little thing you unplugged was your Mass Air Flow sensor and you need it for it to run properly.



ok thanks for the info i had just did a tuneup recently but i will make sure to do it again i appreciate you taking the time to answer this for me once again thank you.


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## Aphterskulspeshl (Dec 22, 2004)

JAMESZ said:


> I PWN him all the time.
> 
> As for your issue I would think it is either the fuel filter or the MAF (Mass Air Flow sensor the thing you unplugged). Just replace those two and see if that fixes the problem.



i know it is not the filter cuz we unhooked the gas line and checked the filter and it is working properly so i guess it is the maf thanks for the feedback i will look into that  i appreciate all the help


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## Aphterskulspeshl (Dec 22, 2004)

SKD_Tech said:


> I think he unhooked it after the problem arose but still. Don't unplug anything you don't know about. It's not real smart.



well atleast you read my problem right i did unhook it after the problme arose and it wasn't me it was my dad and he knew what he was doing to a point and he unhooked it to see if we could narrow the problem down. and if it was worse we could always plug it right back in and it would be the same as it was before thanks for the feedback


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## JAMESZ (Mar 12, 2004)

The thing is your dad DIDN'T know what he was doing if he unhooked it. Don't jump on Balliztiks back about that he was perfectly right in saying what he said. In the future don't unhook things when you don't know exactly what is going on.


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## Aphterskulspeshl (Dec 22, 2004)

SKD_Tech said:


> Can we say pre-OBD I? We don't have one.



no and it just started all the sudden i know i only payed 400 dollars for it but it was running really sound and then just all the sudden this problem came up


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## Aphterskulspeshl (Dec 22, 2004)

JAMESZ said:


> The thing is your dad DIDN'T know what he was doing if he unhooked it. Don't jump on Balliztiks back about that he was perfectly right in saying what he said. In the future don't unhook things when you don't know exactly what is going on.


i didn't jump on no ones back but if he would of read the thing in the first place in stead of asumed my dad and myself just started unhooking stuff randomly then he would of got a diffl reply and he did know what he was doing and he told me it was probally the (mas) and it was going to cost about 300 to 500 dollars i just wanted some imput from some other people who knew about them also. so i didn't jump on anyone. it is always to good to have more than one oppion maybe he didn't know that was the exact thing wrong but he was trying to help his son that couldn't afford to take it in.


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## asleepz (Feb 24, 2004)

Get a new Mass Air Flow Sensor (try a junk yard first) and give it a try. That should fix it.


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## Zen31ZR (Mar 24, 2004)

If you unplugged the MAF and the problem became _worse_, then the MAF is _probably_ ok...... A dead MAF would not affect anything in the slightest, plugged or unplugged. I'd check the TPS sensor, if your dad is any sort of consumate mechanic he'll know what that is and how to test it, they had such things on carbed cars for years before EFI. You may also be dealing with a vacuum leak. I'm also curious if this car is turbo or non turbo. Most likely non, but I have to ask.


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## asleepz (Feb 24, 2004)

Well actually from what he said it seemed to run better with it unplugged "Better" but still better sounds crappy.

So I'd go with the TPS or MAF then. Maybe both


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## Marc Z31 (Jul 25, 2004)

It sounds an awful lot like a MAF issue.


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## Aphterskulspeshl (Dec 22, 2004)

[email protected] said:


> If you unplugged the MAF and the problem became _worse_, then the MAF is _probably_ ok...... A dead MAF would not affect anything in the slightest, plugged or unplugged. I'd check the TPS sensor, if your dad is any sort of consumate mechanic he'll know what that is and how to test it, they had such things on carbed cars for years before EFI. You may also be dealing with a vacuum leak. I'm also curious if this car is turbo or non turbo. Most likely non, but I have to ask.


well it is a non turbo, and thanks again for the information i will make sure to tell him what you said


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## Aphterskulspeshl (Dec 22, 2004)

SKD_Tech said:


> Get a new Mass Air Flow Sensor (try a junk yard first) and give it a try. That should fix it.


ok thanks i have looked into one and they want 75 dollars for it at the junk yard.. but looks like i may just have to pick it up anyways better than selling my right arm and leg lol thanks


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## asleepz (Feb 24, 2004)

Aphterskulspeshl said:


> ok thanks i have looked into one and they want 75 dollars for it at the junk yard.. but looks like i may just have to pick it up anyways better than selling my right arm and leg lol thanks


Do they sell AS IS? Or can you return it in a worst case scenario?


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## playful0 (Dec 26, 2004)

befoire ya buy a mass air flow sensor i would check the fuel filter if you have any rust in it your tank is rusted cost aobut 80 bucks at a rad shop to boil it out and coat it this was the problem on my 78 z and i spent close to 3k on it before the shop desided to give up on it so i took it home switched engines and everything only to have it still run bad. so i checked the gas tank and that was it. it caused the exact problem your having the reason it runs at idle fine is there is alot less pressure demand from it at lower rpm's no clue why the shopp had never thought of that lol.


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## Aphterskulspeshl (Dec 22, 2004)

SKD_Tech said:


> Do they sell AS IS? Or can you return it in a worst case scenario?


as is no return policy


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## Domdogg123 (Nov 12, 2004)

Aphterskulspeshl said:


> as is no return policy


If you've got a multimeter.....you can do this to see if it's a good one.


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## playful0 (Dec 26, 2004)

good idea on the multi tester


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## Zen31ZR (Mar 24, 2004)

Domdogg123 said:


> If you've got a multimeter.....you can do this to see if it's a good one.


Good find. AZ shoulda popped up with that himself. I forsee a sticky in the near future. All of us will probably be doing this at one time or another.


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