hi i just joined the auto forums and i haev a 87 n/a 300zx and i was wanderin if any of u know what could be wrong with my car .it starts fine in the mornin idles fine but when u start drivin it for about 5 min or so it wants to die like it is running out of gas .i haev put the gas treatment in the tank to keep it from freezin and it didnt work .then i tryied a ecu but it came up nuttin except speedometer sensor .it only does it when it gets real cold out side like in the teens. if u all could please help me

hi i just joined the auto forums and i haev a 87 n/a 300zx and i was wanderin if any of u know what could be wrong with my car .it starts fine in the mornin idles fine but when u start drivin it for about 5 min or so it wants to die like it is running out of gas .i haev put the gas treatment in the tank to keep it from freezin and it didnt work .then i tryied a ecu but it came up nuttin except speedometer sensor .it only does it when it gets real cold out side like in the teens. if u all could please help me

it is probably a sensor...

an O2 sensor comes to mind from your description. if i am not mistaking the O2 sensor only activates once the car is at normal operating temp which would explain why it is leaning out your air/fuel mixture after already warm. hope this helps...

O2 sensor would have most likely set a code. Check your throttle body make sure its not all dirty and gunked up. It doesnt sound like your fuel is freezing, it has to get a WHOLE bunch colder than most of us live in for gas to freeze. (I think its in the -60s F) You could also have a vacuum leak that is only showing up when your car gets warm and goes into a "closed" loop operation. Could be a list of things, I suggest you take it to a shop, a good shop, and pay then 2 hours diagnostic and let them figure it out, its alot better than haveing a 1.5 ton lawn jockey in your yard.

O2 sensor would have most likely set a code. Check your throttle body make sure its not all dirty and gunked up. It doesnt sound like your fuel is freezing, it has to get a WHOLE bunch colder than most of us live in for gas to freeze. (I think its in the -60s F) You could also have a vacuum leak that is only showing up when your car gets warm and goes into a "closed" loop operation. Could be a list of things, I suggest you take it to a shop, a good shop, and pay then 2 hours diagnostic and let them figure it out, its alot better than haveing a 1.5 ton lawn jockey in your yard.

but it sounds like the o2 sensor is still sending a signal to the ECU. ECU will only throw a code if it isnt getting a response from the sensor.

coolant temp sensor? if the engine isnt detecting that the engine is warm then it could be flooding your engine with fuel. :dunno:

im betting its a malfunctioned sensor.

well i am puttin a new o2 sensor right now if that aint it what do u think i should do?

well i am puttin a new o2 sensor right now if that aint it what do u think i should do?

take it to nissan. they will be able to diagnose it an hour or better. once diagnosed you will know what to replace. this doesnt sound very cost effective but on these types of cars sometimes it end up being alot cheaper to get it right the first time. so in alot of cases it is cheaper to get the whole car diagnosed by the dealership.

just an idea. it could many different things though it does sound like a sensor problem to me.

ok i might do that next weekend .how much do u think sub frame bushings will cost?

ok i might do that next weekend .how much do u think sub frame bushings will cost?
ehh...

check with deleriousZ, he will post sooner or later. i havent done much shopping for Z31 parts so, obviously i have never seen any before...

clicky (http://www.garymolitor.com/300zx/rear_subframe/rear_sub_frame.htm)