Remington

Haven't posted in a loonnnng time but now I've got a tech question for yall.
Car: 96SE auto, 75k miles
Symptoms: Intermittent high idle.
When I first start the car, idle is fine (600+/- rpm) After driving for a few minutes the idle is 1k+ and if I put it in neutral, idle jumps to 1700-2000 rpm. Requires increased braking effort due to high idle and I'd like to fix it. As I said, it's an intermittent prob but it has been happening more frequently in the past couple months. Turning on/off the A/C seems to have no bearing on the problem. I'm thinking it's vacuum or a sensor but I don't know where to start. Maybe the throttle cable? Don't think it's the idle setting because it idles fine some of the time. Check engine light is not on. I'm hoping someone may have seen this before. Thanks for any help and let me know if you need more info.

sinewave

I think you may be on to something with the throttle cable. If it is at the proper adjustment (turn the adjusting nut until the throttle cam starts to turn, then back off 1-1/2 turns), it may be the butterfly is sticking. Remove the intake snorkel from the TB and spray some carb/TB cleaner in the TB while the engine is running.

bill99gxe

iTrader: (1)

Remington,

It's good to see ya on here again.

I'm copying this over to the 4th gen forum so the resident Maxima expert, Daniel B. Martin, can assist as well.

Daniel B. Martin

I've got a guess. False Air.

Any air which "sneaks" into the engine from a source downstream of the Mass Air Flow Sensor is called False Air. False Air will cause RPMs to increase. The first place to look is the flexible black plastic duct which conveys air from the Mass Air Flow Sensor to the Throttle Body. The engine moves around a bit on its flexible mounts during normal operation. If there is a crack or split in that air duct, engine movement may cause the crack to open and close. Every time it opens, RPMs go up. Every time it closes, RPMs drop.

Please make a careful visual examination of the air duct, and also make this simple test... with the engine idling, grab that air duct and push it back and forth, up and down. Don't use enough force to break it, but just enough to flex it as it was intended to do. If you can cause the idle speed to change, up or down, that is evidence of False Air.