That is part of the Accelerated Warm Up System all Skyactiv Mazda vehicles have.
I would say a huge majority of fuel injected engines operate this way in cool or cold weather from a dead cold start.I've owned my 2023 CX-50 TPP for about a year now. I took it to the dealership about two months ago after an engine malfunction (the PCV hose was improperly installed by the manufacturer; the dealership replaced the hose and clamp).
Recently, I've noticed my CX-50 revving to about 1,500 RPM before settling to around 900 on a cold start. It takes almost 40 seconds for it to settle down to 900, and on its way down it jumps around (1,100 > 1,000 > 1,200 > 1,000....etc). Is this how the car should start?
It is the Mazda Accelerated Warm Up, standard.I would say a huge majority of fuel injected engines operate this way in cool or cold weather from a dead cold start.
Yours may have appeared to just started doing this because of the improperly installed PCV hose.🤔