Yet another wierd idle problem

[MoldyOldy240]

hmmm... this is like, the third or fourth one here in the past week, but all have different conclusions. Lets see here

This happens sparatically ; just started today:

Car: 1991 Nissan 240sx Hatch Back 5 spdPerformance parts: No known after market, only serviced by NissanRecently replaced parts: Previous owners son put a used O2 sensor in 1 month ago (cheap jerk spent 15 bucks to save 25)Engine Codes: 45 (Injection Leak)Symptoms:

Sparactically occurring; when car is in neutral, or when clutch is pressed, the idle will drop from 800 to about 300 and start to choke out. It goes back up with no interference from driver to about 1100-1300 and then will dip back down to 300 a few times. A couple times it has caused the car to die.

This happened while the engine was warmed up.

When it dips there is a heavy rich smell, leaving me to beleive there is no problem with the fuel or spark.

Checked wires, wiggled injectors vigorously to see if maybe it was a loose wire; no change in engine performance. All hoses are recently new (performed by Nissan by previous owner).

Theory:

Since the O2 sensor was used, I went ahead and purchased a new Bosch O.E. O2 sensor to see if this will fix the problem, and am right now waiting for the engine to cool down.

Any suggestions gang if its not the O2 sensor?

I hope the format I am using helps you all understand where I am coming from

[MoldyOldy240]

Update: Replaced O2 sensor; old one was incredibly oxidized (colour was brilliant white) and appeared different then the new Bosch OE spec O2 sensor (Bosch was round with vertical slits, while old one was boxy with circular cuts).

Wiped codes

Drove around the block in second gear at 2,500 rpm for 5 minutes, then let sit in idle in drive way for 8 minutes; no codes were thrown. Engine was still "warm" when car was started.

I'll update tonight after I go X-mas shopping, but I hope I fixed this code at least.

Feel free to post if you have any other theories or comments.

[MoldyOldy240]

No good;this time 34- knock sensor and a 45 injector leak engine code were displaying.

Car had been running for 15 minutes before just fine, about to get on the freeway, stopped at one of those traffic lights on the on ramp, and the car started to cut.

Any one have any ideas? I can't go out in rush hour with my engine cutting out randomly.

[MoldyOldy240]

Alright, so I figured, it must be something with idle control; so I pulled off the intake and the throttle body;the TB was full of carbon and looked like it needed a good cleaning, so I am going to use a degreaser on it tomorrow and re-assemble, make sure I didn't screw anything up. My aim was to grab the air idle control vavle, because in the write up I found on the DE it was attached to the TB, but not so much.

So after sticking it back on, I am going to look at finding it; I am assuming its tucked behind the exhaust mani?

If any one has any suggestions; i.e. what I should use to clean it with, or no you moron the IACV is located here, I would appreciate it greatly as right now I am going on what other people are posting and my own brain; all the FSM I have found have either been link dead are not very helpful.

[janda240sx]

The IACV is located on the bottom of the intake manifold.

[janda240sx]

Sorry. posted on the wrong page, NOT Paying attn.

[MoldyOldy240]

Cleaned out the throttle body; I am going to pack everything up and wait till tax time; the part isn't giving me too much trouble, and the car is still driveable, so it will have to wait.