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Discussion Starter #1
Hey guys, on my 97 Pathfinder, I’ve had a small issue for a while where the idle for the vehicle is a bit high. When the vehicle first cold starts it goes up to 2000 then levels off at 1500rpms until it warms up and drops to a 1000. It used to be around 750-800 rpms.

A little over a year ago I replaced the throttle body gasket and cleaned it also. I’m not sure if it’s because of that.

I tried adjusting the IACV a while back, but nothing changes when doing so. Now I’m afraid I have messed up the settings on that.

At times when you start it up warm it will idle close to normal but then rise back to 1000rpms.

Also, I notice when on the highway and I let off the throttle at around 50mph only with the A/C on, the tach will bounce a few times before stabilizing. No jerking or hesitation is felt in vehicle, but the rpms do this.

Any ideas? Was thinking it could be thermo element wax on the throttle body or bracket may be bent.

vehicle is well maintained: New plugs, distributor, tps, plug leads, throttle gasket, maf sensor, transmission fluid change, 3000 mile oil and filter change, new battery, new fuel filter, air filter, new belts. Had a hot start stumble that went away after running a can of Bg44k.

occasionally have a p1441 code that comes on and off every so often. Can never find the reason for that code. Changed evap solenoid and purge valve and still happens.
 

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NF Mod/Nissan Master Tech
2006 Pathfinder LE, 2003 Frontier SVE
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9,767 Posts
If the thermo wax is bad, it could do that, or, if there is a clog in the coolant path that warms the thermo wax. With the vehicle cold, start the engine and see if the plunger retracts as the coolant gets up to normal operating temperature. It would also be a good idea to make sure the coolant actually IS getting up to temperature and not staying cold due to a stuck open thermostat. If the coolant gauge needle stays on the low side of the gauge, I would start by replacing the thermostat. If all tests good, then I would adjust the TPS per the factory service manual procedure, first, followed by adjusting the ignition timing and base idle with the ECM in "timing set mode" (procedure is also in FSM). If the adjustment screw on the IACV-AAC valve is turned all the way in and the idle is still too high, I would suspect a faulty IACV-AAC valve. Nico Club's side has free, online service manuals.
 

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Discussion Starter #3
If the thermo wax is bad, it could do that, or, if there is a clog in the coolant path that warms the thermo wax. With the vehicle cold, start the engine and see if the plunger retracts as the coolant gets up to normal operating temperature. It would also be a good idea to make sure the coolant actually IS getting up to temperature and not staying cold due to a stuck open thermostat. If the coolant gauge needle stays on the low side of the gauge, I would start by replacing the thermostat. If all tests good, then I would adjust the TPS per the factory service manual procedure, first, followed by adjusting the ignition timing and base idle with the ECM in "timing set mode" (procedure is also in FSM). If the adjustment screw on the IACV-AAC valve is turned all the way in and the idle is still too high, I would suspect a faulty IACV-AAC valve. Nico Club's side has free, online service manuals.
Thanks. I know there’s a engine coolant temperature sensor and another smaller sensor next to that for the temperature gauge. You’re not speaking of these right?

I’ll also try to replace the thermo wax to see if that helps. Any experience on that?
Because when the engine is warm the roller doesn’t move all the way to the second tick mark. But if you were to use a flat head and move it back the idle drops down to normal.
I’ll try to get a picture up.
 

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NF Mod/Nissan Master Tech
2006 Pathfinder LE, 2003 Frontier SVE
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9,767 Posts
I didn't say anything about a sensor, so I'm not sure what you're asking? Sounds like the thermo wax could be not retracting all the way back, but just make sure the coolant is getting hot enough at the throttle body. Best way is with an infrared thermometer.
 
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