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Where is the idle speed adjustment screw?

16K views 6 replies 6 participants last post by  amc49 
#1 ·
Hi all

I have driven my Altima 1998 for a week now, I am impressed by its 2.4L engine and power and torque. I just have to get used to the stiff clutch and notchy shifting compared to my older Corolla

Even when the engine has warmed up, it idles fast around 1000rpm and I think it it should be more in the range of 750rpm

Apparently there is a screw you can turn to adjust the idle speed, can anyone show me where or post a picture please

thanks

-- proud new owner of a used 1998 Altima GXE, 5-speed, 110000km and counting
 
#2 ·
Idle Speed screw is on the passenger side of the engine inbetween the first two (or last two however you want to look at it) air intake pipes

 
#3 ·
first thing you need to do is make sure its the idle screw setting the idle, or either the throttle cable or cruise control cable is doing it. if either of those is too tight, it can raise your idle.
you are correct though, idle should be around 750 RPMs. just check those cables before you go messing with the screw!

and yea, the tranny is notchy and the clutch is stiff (hydraulic...) but once you get used to it, its no biggie. and its a big step up from a Corolla!
 
#5 ·
Ok this last statement is not true.. there is definately an adjustment screw on my 1999 late/early 2000 GXE adjust from directly above with long phillips..also, b4 that, disconnect your throttle/position sensor. On firewall side of throttle body.....the top plug. Then adjust it. Then plug sensor back in. If you adjust that black fiber screw on ACC VALVE without dis. Throttle position sensor it can throw that off.
 
#7 · (Edited)
There may BE an idle speed screw, and messing with it is often how the car gets messed up to not hold idle correctly. People make that mistake by the thousands.

The computer has software to hold a set idle speed regardless and often messing with that screw seems to do something until car gets cut off and then you drive it again. The computer detects the wrong idle speed and changes things to get it back and one of them is any idle speed control device, which needs to run about in the middle of its' range, not doing so because somebody messed with idle speed can create problems and even pop engine codes. It leads to wrong TPS range readings and thus load on the engine throughout the fuel map. It can also lead to hanging idle and where the original poster may have been.

Say you have a slight vacuum leak within idle fuel map parameters, the engine will idle up, then you MIS-set the idle back lower and now driving around with a vacuum leak to slowly burn the engine down.

Why most of them have been hidden or disabled now, they cause the dealers untold warranty issues for nothing but people messing with things they don't grasp fully.

Other things can happen too.

You don't change idle speed on any electronically controlled car without considering what can go wrong doing it, usually it is a mistake done to cover another issue not found. It is supposed to be left alone on modern cars and never touched.
 
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