Hate to do this, but I really need your help guys (hot idle problems)

[ragenasian]

Okay first I searched and couldn't really find anything on my problem. If I missed it I will apologize in advance for that but I am about to scrap my CA 200sx s13 and you guys are my last resort. The car ran fine before it was parked for the winter. During that time a FMIC was installed and a new water pump. Now the following problems have arised after pulling it out finally.

FLOAT told me the change the water temp sensor but I have a few more details to add.

Anyways when this thing is cold it runs fine. Once it gets to operating temperature and you stop at a light the rpms just drop off to nothing. I put the car's ECU into diagnostic mode and got 55. Nothing else followed that and I tried this on two separate ECUs. However on the trouble code sheet I didn't see the temp sensor. I only see the fuel temp sensor. Am I correct in that the ecu does not check the water temp sensor, is it called something else, or is it on the sheet and I am just a dumb ***. The car will also stay running as long as you keep on the gas and it has no problems whatsoever when you floor it.

I also took it to a mechanic who said he couldn't figure it out. He works on exotics so I figured this guy could fix it but maybe it wasn't worth his time who knows.

The car is also blowing white smoke too. The car sat over the winter (about 5 months) without being run so I am thinking maybe the turbo. It didn't blow any smoke whatsoever before I parked it. I got a T28 that is within spec (checked by a turbo company) waiting to go into it but I have to have this thing running before that happens.

Please help because I have about 20 more days to figure out what I am going to do before the ARMY is going to want their plates back.

[Axlerod]

Well you never know what can happen while the car's sitting.

First I would check the A.A.C. Valve... you can find the proceedure on FSM page EF & EC-106

If that's ok, then check out the o2 sensor. Disconnect it and see if the problem goes away. If it does, replace the sensor.

[ragenasian]

Okay I unplugged it and it seems that the problem has gone away. It will start up fine now and idle with no problems. So my question if somebody can explain is "what does the o2 sensor have to do with the idle?"

This might sound stupid but I would like to know what it has to do with the idle of my car when hot. THANKS