Please Help: Hunting Idle 1500-2000 RPM (w/ Video)

[designasaurus]

Hey R3V,

I've got a hunting idle between 1500-2000 RPM's. Coincidence or not, this occurred roughly at the same time as the new gas I pumped hit the motor. Does anyone have any thoughts or advice on my situation? Help is greatly appreciated!

See Video here:

http://www.youtube.com/watch?v=gvi8TrsXx0w

What I've already ruled out:
Coolant Temp Sensor (Replaced)
Idle Control Valve (Swapped w/ working unit)
MAF/Intake (Swapped w/ working unit)
90% sure its not a vacuum leak

Other Possibilities:
Bad Oxygen sensor
Throttle Position Sensor

[jlevie]

A smoke test not run long enough or at insufficient pressure might result in a 90% confidence, but a visual inspection and/or carb cleaner is more like a 30% confidence level.

Before you throw more parts at the problem have a smoke test run. Well, since an O2 sensor has a scheduled replacement interval of 100k, and since most every E30 has that much mileage, you do need to change the sensor.

[dnguyen1963]

Big time vacuum leak!

[Gregs///M]

Agreed, extra RPM's usually indicates vacuum leak. Have smoke test run or try blowing cigar smoke into one of your vac lines such as brake booster. Then vacuum test brake booster.

Or have a mechanic "T" into your evap and crankcase to perform the smoke test.