Rough Idle at Start Up for two minutes - Then OK WK2 2012 CRD 3.0

[Moonfleet]

Rough Idle at Start Up for two minutes - Then OK WK2 2012 CRD 3.0
Can't seem to get to the bottom of this ? On warm days [26 c] alls fine but on days when say 18 c the idle is rough and if you drive off without waiting around 2 minutes hear a clamping sound? Now I loaded OBD Fusion app, and noticed at start up the Intake air temperature was recording 52 c when the ambient temperature is 19 c. This cannot be .... This reading settles down after ten minutes to 24 c when at 19 c Ambient. I changed the MAF made no difference ...... So what are your thoughts please on this one.

[drover]

I had similar with my old Grand so it could be the same with these, the PCM gets its ambient air temperature from a sensor which is located near the radiator as well as from the MAF but its on the outside behind the grill, so it gets outside air flow, its just a plastic thing...... in my case the plug was loose, and the outside temp display in cabin was way out, engine was rough as but once I got the plug connected properly everything went back to normal.........
Just a guess on my part though.......
There are tests you can do on the MAF to check operation, if you cleaned it with sensor spray they do need a good dose and be allowed to dry before use... with all these sensor because of the minute voltages used a bad contact will throw everything out....

[Treebreakerbob]

Just replace the fuel pump relay, a $10 fix with a Narva one. One of the symptoms is bad starting on colder days

May not be your issue but it’s a cheap item to rule out and with my experience some relays don’t last 500 kilometres before playing up. It’s the one on the ecu aft of the coolant header tank