Idles up and down

UHSNOEBIRD

MEMBER
1997 NISSAN TRUCK
2.0L
4 CYL
4WD
MANUAL
177,000 MILES

My truck idles up sometimes to 1,500 rpm's and then down and sometimes quits. It doesn't show any check engine lights. I know the distributor cap, rotor button, plug wires, gas filter and so on are good.
I was thinking it might be the idle control valve I call it. I don't know the technical name for it.
Does the idle control valve give me a check engine code if it's bad or does the IAC give a code is it goes bad?

3 Replies

KASEKENNY

MECHANIC
18,907 POSTS

More than likely you are correct that it is the idle control valve. Your specific component is called the idle air adjusting unit.

If it were me I would go ahead and replace it. You can clean them but again, they are cheap enough I would just go with new one and then clean the old one so you always have a spare.

https://www.2carpros.com/articles/idle-air-control-valve-service

Let me know if you have questions. Thanks

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Wednesday, December 25th, 2019 AT 1:11 PM

UHSNOEBIRD

MEMBER
342 POSTS

I don't have any check engine lights on. plus I checked for codes with my diagnostic tester and it showed none.
I've been told this might be the problem this part fuel injection thermostat in this web link:
https://www.carid.com/original-equipment/fuel-injection-thermostat-mpn-1639112g00.html?singleid=1795967990&url=4904360#warranty

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Wednesday, December 25th, 2019 AT 8:13 PM

KASEKENNY

MECHANIC
18,907 POSTS

It could but if you monitor the fuel pressure you should see a change that corresponds with the surging if it is fuel related. If you don't then it is air control related.

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