After some advice please.
I have a W reg 1.8 plastic topped engine in a 146. Engine has only done about 30k miles.
Tickover is erratic. You will pull up and the tickover will be fine. Sometimes after a variable time tickover will start oscillating between 1500 and 500rpm. This can continue or just as quickly stop.
Other than this engine runs fine, doesnt use water, not missing, no ecu lights on.
Might be worse when engine is hot, heater off.
Can also be affected by switching air-con on
Any suggestions greatly appreciated.