I notice that sometimes when put my car in Neutral or Park, the engine revs to about 1500 RPM, even after reaching operating temperature. I can predict when this will happen now by the amount of resistance against the brakes when I stop at a light. The tach will also show the car at about 1000 RPM when stopped in Drive, which is high. I found that if it does this, I can put the car in Neutral (it will go up to 1500) and tap the pedal lightly - the engine revs to about 2000 RPM and then settles down to a more normal 800 RPM. When I put it in drive, it behaves normally again.

I have cleaned out my throttle body in the past few months. I also checked the throttle cable and springs for tension, and they're fine. Anybody have any thoughs why this happens? It doesn't happen all the time, which is weird. Any help is appreciated!

 

I have a 5spd and mine does the similar thing also. I'm just as clueless as you are though but I figure it might help ya feel better to know that other Maxs' do it too.

 

I have no explanation either, but mine did it for one summer, then it stopped the next spring (didn't happen over winter either). Took it to Nissan, and they had no idea what it was. It's been 2 years now, and no recurrence, so there's hope....

 

While playing around at work (Turnersville Nissan) I found something interesting about this idle situation. It seems this has been documented a few times and that there is a solution to it. Supposibly to fix this the TPS has to be replaced because of one of the switches getting stuck off. When this switch is off, it causes the car to idle around 1400 rpm's and when it is on the car idles normal at around 600 or so rpm's. I don't remember the specifics but I figured I'd let you know cause I am planning on replacing mine after seeing this.

 

This is interesting. You can very easily test the TPS with an ohm meter. The other swith detects the fully closed position.

I'd be looking at the IAC valve too. That valve controls your idle speed. hint hint.... The TPS has to be set correctly as well. There is a procedure in the Service Manual for this and it goes like this....

Put your ohm meter on pins 2 and 3. With the throttle plate fully closed you should have .5K of resistance. WIth the throttle plate fully open you should have 4.0K of resistance. The resistance should increase smoothly as you open the throttle plate.

The 2nd TPS sensor is a switch. Put your ohm meter on pins 5 and 6. With the throttle plate fully closed you should have continuity. Open the throttle plate slightly and you should get no continunity.
To adjust this TPS "switch". Place a .3mm feeler gauge between the throttle stop screw and the throttle lever. Continunity should be indicated. Next remove the .3mm and insert a .4mm feeler gauge. At this point no continumity should be indicated. Adjust the TPS as needed to obtain the correct readings.

 

My car does the same exact thing.. I noticed this just the other day.. I have a 5spd also. I came on the board to look to see if anyone else had it and sure enough there it was.