Why does my car idle high in park or neutral

TOINFINITIANDBEYOND12

MEMBER
1996 INFINITI I30
120,565 MILES

I have a 96 infniti I 30. I just took apart the top of the engine including the UIM and LIM, replaced all the manifold gaskets, the knock sensor, the fuel filter, and cleaned the h*** out of the Intake Manifold from the throttle plate to the intake valves. After all of that, just for good measure, sprayed some seafoam into the intake with the car running after I put everything back together. My question is: after all of that, the vehicle still idles at 850 rpm in park (its an auto trans) normal is 700-800. Why is it still high?

2 Replies

ASEMASTER6371

MECHANIC
52,797 POSTS

It is computer controlled. No adjustments available. 50 rpm is not much. I would leave it alone.

Roy

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Tuesday, September 4th, 2012 AT 12:19 AM

KHLOW2008

MECHANIC
41,815 POSTS

IDLE SPEED

1. Warm engine to normal operating temperature. Check and adjust ignition timing (if necessary). Turn engine off. Disconnect throttle
position sensor connector and restart engine.

2. Check idle speed, (650-750rpm With transmission in Neutral and no electrical load on engine). If idle speed is not within specification, snap throttle to 2000-3000 RPM, 2 or 3 times, under no-load and then allow engine to return to idle.

3. Locate idle speed adjustment screw. See Fig. 4. Rotate idle adjusting screw clockwise to decrease idle speed and counterclockwise to increase idle speed.

4. Turn engine off. Reconnect throttle position sensor connector and restart engine. Run engine at 2000 RPM for about 2 minutes under no load, and then allow engine to return to idle. Idle speed should be as specified.

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