I get a slight "buzzing" sensation in the steering wheel when my car is at idle. The idle for my car, equipped with an automatic transmission, is correctly adjusted to 700 rpm. The motor mounts are ok as well and the throttle body was recently cleaned. What else might I need to check?

 

the MAXFAQ section linked above, which discusses setting the idle. Most likely, you won't get rid of that "buzz" until you're at least 800rpms or so. Give that a try and see if it helps.

 

I agree with Bill99gxe. Try adjusting the idle up or down to achieve a smooth idle.

Go to Steve Cutchen's excellent MaxFAQ page:
http://web2.airmail.net/scutchen/max_faq/

Click on SUBTOPICS below Maintenance.

Click on Adjusting 4th Gen idle speed


You might also walk all around your car while the engine is idling, listening for any kind of sympathetic vibration. Is the hood vibrating? You can eliminate that by adjusting the black rubber hood support cushions which are located at each end of the radiator support. These cushions are spiral cut so you may adust their height just by grabbing them with your fingers and twisting.

 

Hmm...that's funny. I get the buzzy idle when my idle speed falls below 600 or so. It is vibration free and rock solid when I turn on the AC, which bumps the idle up to 650 or 700 on hot days. The thing with Maximas is that no matter how you adjust the idle, the ECU will slowly bring it back down to the factory levels over time. It sucks, but if you want a temporary fix, then the idle adjustment screw is the only way to do this.

 

Hmm, i have a 97 I30 with the same rough idle problem, most noticeable when the headlights/foglights are on. The dealer replaced the EGR and BPT valves under warranty, and that hasnt really rid the problem. On very hot days, the problem is almost never there, but when its cooler out (50 degrees F and under), its pretty bad. On a cool day, if I start my car, I hear a helicopter type chopping noise, plus a deep bassy rumble (all exhaust is stock) accompanying the rough idle. Once the engine reaches full warm, the roughness is decreased, but the helicopter chopping-type noise is still there and so is the bassy roughness that I can hear. This all happens in either R or D, and when I shift into P or N, its butter-smooth and no bassy rumble noise. Whats the deal!