# Reviving up and down when the Engine is Not warm.



## lovelycael (10 mo ago)

Nissan VG 30. Pick up 1998 model. V6 4x4 hardbody. Everytime when I start it in the morning the revs will go up to 4000/ps then down then idle low for few seconds then up again until the engine oil gauge is up a little after 2 - 3minutes. the car will start to idle okay.

i tried to look for faulty licks on the intake mainfold n check few sensors but cuddnt help.. what might cause this problem as i changed the intake gasket but still same issue.. I








also changed the MAF sensor.


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## nissanmanahil (4 mo ago)

Does your car have a thermostat?


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## lovelycael (10 mo ago)

nissanmanahil said:


> Does your car have a thermostat?


Yes the Radiator cap has one..the one with a spring n rubber end.


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## rogoman (Dec 16, 2004)

lovelycael said:


> Nissan VG 30. Pick up 1998 model. V6 4x4 hardbody. Everytime when I start it in the morning the revs will go up to 4000/ps then down then idle low for few seconds then up again until the engine oil gauge is up a little after 2 - 3minutes. the car will start to idle okay.
> 
> i tried to look for faulty licks on the intake mainfold n check few sensors but cuddnt help.. what might cause this problem as i changed the intake gasket but still same issue.. I
> View attachment 9581
> ...


The IACV-AAC valve might be faulty.


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## lovelycael (10 mo ago)

johnmark9120 said:


> It helps distribute oil throughout the engine and get the engine block and engine oil up to temperature. *Revving the engine won't speed up the process*. In fact, that could cause easily avoided damage. Cold revving causes abrupt temperature changes that create stress between the engine's tight-fitting components


The car revs by itself up and down when you start it.. then after a minute when the oil temp goes up a bit it will go down to 500 - 700 rps.. a little up and down not stable..


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## lovelycael (10 mo ago)

rogoman said:


> The IACV-AAC valve might be faulty.


Will check it later..Thanks


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## BlueT31ZA (5 mo ago)

I'm gonna guess idle control valve. Maybe MAF/MAP sensor


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