# 94 300 hesatation



## 300zx5spd (May 30, 2004)

ok for some time now my 94 N/A 5sp had had a hesatation at low rpms when the car is warm, like it has no power in first off the line.or any other gear for that matter then at 3000rpm it kicks in. i know thats normal for most imports but this is different, my girlfriend mazda percidia can kick my butt!! when the car is cold however the car run perfect, only after it warms up do i get problems. i mean i can't even merge into tracffic it has so little power. i changed cats and fuel filter. but it's still there. the car also gets slight little jolts when am going up a hill and giving it gas. nothing big but i can feel it. i have also just had the timeing belt done. my thoughts are an o2 sensor or egr valve and am doing the plugs later today but if anyone has any ideas please let me know thanks. 

P.S the car also is having problem holding idle it jumps up and down like it wants to die but never does am looking for a vacume leak but no luck so far, the car will hold better if i turn the auto Climate Control on.


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## Zen31ZR (Mar 24, 2004)

300zx5spd said:


> ok for some time now my 94 N/A 5sp had had a hesatation at low rpms when the car is warm, like it has no power in first off the line.or any other gear for that matter then at 3000rpm it kicks in. i know thats normal for most imports but this is different, my girlfriend mazda percidia can kick my butt!! when the car is cold however the car run perfect, only after it warms up do i get problems. i mean i can't even merge into tracffic it has so little power. i changed cats and fuel filter. but it's still there. the car also gets slight little jolts when am going up a hill and giving it gas. nothing big but i can feel it. i have also just had the timeing belt done. my thoughts are an o2 sensor or egr valve and am doing the plugs later today but if anyone has any ideas please let me know thanks.
> 
> P.S the car also is having problem holding idle it jumps up and down like it wants to die but never does am looking for a vacume leak but no luck so far, the car will hold better if i turn the auto Climate Control on.


Sounds like you ISC (idle speed control) motor is either lazy or not accepting ECU inputs (broken wire ?). Seems like it works ok if the A/C is on. When the A/C is turned on it kicks the throttle open just a hair to raise the idle so the car won't die when the compressor kicks on.
As far as the sluggishness is concerned , theres a ton of sensors and stuff that controls how the car behaves when it is warm , I'd say one of them is definitely bad. Coolant temp sensor , O2 sensor , possibly the EGR valve , idle air control valve , any of those will absolutley kill power if not working correctly. Can you tell if the car runs rich at all when this is going on? Maybe have your g/f follow you as you drive around , or follow her when she drives your car so you can see if there's any black smoke while accelerating.


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## 300zx5spd (May 30, 2004)

no the car has no black smoke and is not running rich. the car just seems to be bogging. and i ment to say that even when the AUTO climate contol is on it still has a bit of a jumpy idle just not as noticable


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## Spongerider (Nov 18, 2002)

300zx5spd said:


> ok for some time now my 94 N/A 5sp had had a hesatation at low rpms when the car is warm, like it has no power in first off the line.or any other gear for that matter then at 3000rpm it kicks in. i know thats normal for most imports but this is different, my girlfriend mazda percidia can kick my butt!! when the car is cold however the car run perfect, only after it warms up do i get problems. i mean i can't even merge into tracffic it has so little power. i changed cats and fuel filter. but it's still there. the car also gets slight little jolts when am going up a hill and giving it gas. nothing big but i can feel it. i have also just had the timeing belt done. my thoughts are an o2 sensor or egr valve and am doing the plugs later today but if anyone has any ideas please let me know thanks.
> 
> P.S the car also is having problem holding idle it jumps up and down like it wants to die but never does am looking for a vacume leak but no luck so far, the car will hold better if i turn the auto Climate Control on.


What you just described about idle hunting sounds like your o2's are bad. On the Z32 the O2's are only used at idle (closed looped) but once you put your foot on the gas it's open loop and does not use the O2's at all. From what you described you also have a couple of different things going on.

You also might want to change you fuel pressure regulator and fuel dampner. They are know to go out on high milage Z's. I would also invest in some good fuel injector cleaner Redline, Amsoil does the trick for me. And replace your spark plugs with OEM NGK. 

When is the last time you did a major tune up?


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## Zen31ZR (Mar 24, 2004)

Spongerider said:


> What you just described about idle hunting sounds like your o2's are bad. On the Z32 the O2's are only used at idle (closed looped) but once you put your foot on the gas it's open loop and does not use the O2's at all. From what you described you also have a couple of different things going on.
> 
> You also might want to change you fuel pressure regulator and fuel dampner. They are know to go out on high milage Z's. I would also invest in some good fuel injector cleaner Redline, Amsoil does the trick for me. And replace your spark plugs with OEM NGK.
> 
> When is the last time you did a major tune up?


I mentioned the O2s , but somebody wasn't listening.


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## 0341TODD (Nov 15, 2003)

Hey did you check your 02 sensors?



hahaha- sorry guys-I having a "I think Im funny" attack again.


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## Spongerider (Nov 18, 2002)

[email protected] said:


> I mentioned the O2s , but somebody wasn't listening.


I know. I was not dissagreeing with you.


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## Zen31ZR (Mar 24, 2004)

Spongerider said:


> I know. I was not dissagreeing with you.


Oh , I knew you weren't , I was just being sarcastic.


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## 300zx5spd (May 30, 2004)

am not completely sure but the car seems to run better the colder it is, nissan wants 129.00 cnd$ per o2 sensor is it best to get one form them or an after market one?. also what kinda fuel milage do u guys get. am getting 250miles to a tank all hwy driving almost. i just had the ac done and they said it had no leaks but the ac cuts in and out. like gets cold them goes to room temp and repeates it.


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## Spongerider (Nov 18, 2002)

300zx5spd said:


> am not completely sure but the car seems to run better the colder it is, nissan wants 129.00 cnd$ per o2 sensor is it best to get one form them or an after market one?. also what kinda fuel milage do u guys get. am getting 250miles to a tank all hwy driving almost. i just had the ac done and they said it had no leaks but the ac cuts in and out. like gets cold them goes to room temp and repeates it.


250 per fill up? What mods have you done?


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## 300zx5spd (May 30, 2004)

NONE the car is stock other then the the new cats and mufflers


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## Zen31ZR (Mar 24, 2004)

300zx5spd said:


> NONE the car is stock other then the the new cats and mufflers


 New cat. Now , why would it need a new cat. Old one get plugged up? sounds like a bad 02 to me......


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## 300zx5spd (May 30, 2004)

well thats what the thought was cause it was running fine cold and after a while it started to bog out and run like crap..... so cat must be getting pluged i thought and after riping it all out i found they were fine but replaced anyway. i'll give the o2's a shot. i just hate 300$ what if's


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## Zen31ZR (Mar 24, 2004)

300zx5spd said:


> well thats what the thought was cause it was running fine cold and after a while it started to bog out and run like crap..... so cat must be getting pluged i thought and after riping it all out i found they were fine but replaced anyway. i'll give the o2's a shot. i just hate 300$ what if's


Get an O2 sensor guage and hook it up to the 02 wires to see if it is in fact , dead. The guage itself is like $60 , I think , and if nothing else it'll help you keep tabs on the health of the sensors. The before cat sensor is much more important then the after cat sensor , the aftercat sensor just keeps tabs on whether the cat is working properly. Also , don't buy the 02 sensors from the dealer or whereever , get them from Checker or Autozone , probably be about 1/2 the cost. I've never paid more than $70 for a heated 02 sensor from there. And you can probably get a generic 4 wire heated o2 sensor for about $30 (I'm assuming their 4-wire , I could be wrong) but you'll need to use your old connector.


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## 1slowZ (Jul 8, 2004)

from what it sounds like you might want to check your plugs if you haven't already............the same problem happened to me and the same day i changed the plugs and i never had it again


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