[ProV1x]

car: 1997 E420, M119 motor, 107k miles

Car starts, runs, and drives great. 25.8MPG on the highway. Smooth, fast acceleration, no abnormal noises. Spark plugs, connectors, serpentine belt replaced recently. No Check Engine or malfunction lights on.

Problem: When driving around and coming to a complete stop at a traffic light, the rpm would drop to just below 500rpm and engine will almost stall. Car will shake, but the computer will shoot the rpm back up to compensate. This will go on every 5-10 seconds until I start driving again. Basically the RPM will never stay the same but always move around at idle.

After searching the forums, it could be one of many reasons, such as

1. bad spark plugs
2. bad Mass Air Meter
3. bad engine mounts
4. bad Oxygen sensors (which ones?)
5. vacuum/air leak on vacuum lines
6. clogged fuel filter
7. bad CPS sensor



Now the last thing I want to do is start throwing new parts on her and keep spending $$. But because there is no CEL on, pinpointing where the problem is tough.

Any ideas/suggestions??