Hi....

 

My name is Kristinn and I have problem with my Z.

I own a 300zx two seater ´90 US edition it has 160.000 miles on it.

It has A/C, I´m having problems with the idle, when the A/C is on, the idle

is steady at 1100rpm but when it´s off it rocks up and down from 300rpm up

to 1600rmp. I have already changed the throttle position sensor and levelled

it of at 4,7 volts but it still doesn´t idle like it should. Also, when I

disconnect one vacum line in the engine it idles correctly, but it can´t be

driven like that, but when I connect the vacum line it starts rocking from

300rmp to 1600rpm. My problem only occurs when the car is idling not during

driving.

I have taken the car to a mechanic and he doesn´t know what else he can do,

is there any way you can help me with problem?

 

Thanks in advance, hope to hear from you soon(my car has been in the shop

for 2 weeks, and I´m dying to start driving again.

 

Kristinn S Kristinson.

 

_________________________________________________________________

 

 

 

Hmmm, this looks familiar !

 

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Z32 technical article index - 300zx.org.uk

Kristinn,

from the sound of it the idle adjustment of your car is too low.

 

there are a few things you can try:

-adjust the idle with the adjustmentscrew at the back of the engine

-give the throttlebodiesa good cleaning

-reset the ECU (disconnect battery for at least 6 hours)

-check the IAA-valve in your car. (remove it and either replace it or clean it if possible)

 

-Eric