Failed Emissions Idle Test

[NateDogg]

Well,

After changing the heater core on my '91 240sx, which took a month due to parts delay, I had to get the car smogged. I failed the HC and CO parts of the idle test but the driving test passed easily. Also the NOx registered a 0 while driving (wasn't tested it at idle). Here are the symptoms. -The car is idling very rich and when the throttle is pressed at idle it almost bogs down. -The brand new O2 sensor is stuck at either extremely high voltage or extremely low voltage. The O2 only works properly if the gas pedal is depressed. - Engine has a sound that is similar to when someone is filling up a balloon with air (vacuum leak?)- The engine stalled while idling a short while before this has happened and felt like it was running on 2 cylinders. I had to basically floor it and it went away. I think it could have been the EGR getting stuck with carbon, which is why the EGR is one of the suspects.

So far I've checked the following:1) fuel pressure (34psi at idle with vac. hose on regulator)2) spark (Aurora 100kV coil)3) TPS (set at .41V)4) MAFS (registered 1.0V at idle)5) AIV (cleaned but wet with gas on the inside!)6) O2 - brand new - only works at 1100+ RPM7) Catalytic converter - new8) Engine Temp Sensor resistance9) Fuel injectors - ultrasonically cleaned

The only things I can come up with are the EGR (similar idling feeling as when our van had its EGR stuck) or possibly the AIV reeds are sticking up too much off their plate. This is a pretty major idling problem that I have to get fixed in order to insure my car. I appreciate any suggestions you may be able to offer.

Nate