Why did My BMW start reving up & down after engine got warm?

[sunyq]

This problem with my 1999 523 has recently started. when the engine is warm the RPM started going high and low sometimes very high sometimes very low this dose not happen when the engine is cold that is on cold start.

what is this

[vanvick]

RPM is not working

[zuluu]

its a good start if you check the engine using a tester if there is a problem with the engine.

[individual]

in most cases it's the air mass flow meter (or "air mass gauge" - don't know which term is used here in UAE). Costs approx 300 AED only for the material