Random idle problem

Evaldas

I haven't found anything similar in this forum so new thread.
It is 2002 opel astra z22se engine. Pretty good maintained.
however something happening. Randomly I get "check engine" light on and it starts idling baldy (high idle like 1.5k revs). After this I can't rev more than _3k. If I shut down engine and start it again - "check engine" light is on but engine working nice again.
Any ideas what causes this?
Cheap obd reader does not show any errors (the one that I own)

vocky

you need to use a good code reader and find out what the problem is, as it is limiting the revs it will be something like the throttle body or map sensor.