sr20 shaking at idle, and blown motor mount

[br9ja]

My 1996 G20 sr20de shakes the cabin when in gear and at idle. This car has blown 3 torque mounts in a short while, until I filled it solid with epoxy resin. However, it is still shaking when the A/C, or transmission is engaged. The diagnostic system pulled a code P0505- idle control malfunction, I checked both the idle air control valve, and the Auxilliary air control unit for electrical problems and they both tested in the correct range of resistance.

I just got back from a service shop and they told me they could not find anything wrong with the car.

I drive 20+ miles to work and my mileage has dropped from 33 mpg to maybe 22. Please help

[nametakennow]

Hmm... Only time I've ever seen this was a '69 Mustang, the driveshaft fell out about 20 minutes later. So, my only thought is that your transmission is dying. Did you get the symptoms to repeat for the mech? That's the key. Anyway, a used transmission should be easy to come by, if it's even the whole thing. I'd think it'd be in the torque converter assembly.

[br9ja]

The symptoms happen constatntly, so the tech should have had no problemHowever, the only time this doesn't occur is during cold starts. This leads me to believe that it may not be a transmission problem. As you probably know the engine electrical works on open loop during cold start up. Is there any chance the O2 sensor could cause these problems. My air tube broke in half when the motor mounts went out and I replaced it with a cheap ram air tube, but I am currently trying to locate a stock air tube to eliminate any chance of vaccuum problems. Thank you for your help

[nametakennow]

If the O2 sensor is getting really bad readings and causing terrible A/Fs, you may be getting serious misfire, and I suppose that's one possibility.

How is your idle in terms of rpm?

[01turbosentra]

i trow the same code and the motor shakes as well

[br9ja]

What are A/F's ??

To answer your idle question is as follows:

Cold: idle is approx. 1300 and then drops to 1000 in gear with no vibration

Hot: idle is approx. 1000 and then drops to 600-800 in gear with serious vibration

I have previously tried the idle adjustment screw to no avail, however I did replace the stock air box (still attached to after market tube) and my gas mileage has seem to go up somewhat. I try not to make to many changes at one time in order to make trouble shooting easier, thanks again for your consideration.

[nametakennow]

A/F - air/fuel ratio

Cold idle sounds fine, hot idle should be around 800.

[RED_DET]

The motor mounts will make the car shake @ idle especially with A/C on. I put torque mounts in the Spec V and had to take 1 of them out because the vibration was unbelieveable, especially when a/c or fans kicked on. I even had Nissan adjust the idle up and it still didn't help.

You should be able to adjust the idle screw and get some type of response. If you turn the screw and the idle never changes, you may need to replace or clean the AIC valve.