As temp sensors go bad, the resistance tends to drift upwards, which is indicative of a "colder" temperature.

If this is what's happening (likely), the computer thinks that the car is getting more air intake than it is, since cold air is denser than warm air.

If the computer thinks that it's getting nice thick cold air, it will increase the amount of fuel delivered to keep the mixture correct. But, if it's just a faulty reading then you wind up with a rich condition.


-tp

Still doesn't explain why it would have problems cold starting with everything plugged in. It starts warm fine and runs fine when warm.

Doesn't matter, it runs fine mechanically. I'm not going to worry about it for now.....any car that can pull 107mph in 3rd gear at 6000rpm counts as running GOOD in my book.

__________________
-diesel is not just a fuel, its a way of life-
'15 GLK250 Bluetec 118k - mine - (OC-123,800)
'17 Metris(VITO!) - 37k - wifes (OC-41k)
'09 Sprinter 3500 Winnebago View - 62k (OC - 67k)
'13 ML350 Bluetec - 95k - dad's (OC-98k)
'01 SL500 - 103k(km) - dad's (OC-110,000km)
'16 E400 4matic Sedan - 148k - Brothers (OC-155k)

Swapped in a new intake temp sensor and idle control valve (both from the junkyard), problem solved! It fires right up now and idles smooooth! Not bad for $10!

I did throw about $250 of parts at it prior to this though.

__________________
-diesel is not just a fuel, its a way of life-
'15 GLK250 Bluetec 118k - mine - (OC-123,800)
'17 Metris(VITO!) - 37k - wifes (OC-41k)
'09 Sprinter 3500 Winnebago View - 62k (OC - 67k)
'13 ML350 Bluetec - 95k - dad's (OC-98k)
'01 SL500 - 103k(km) - dad's (OC-110,000km)
'16 E400 4matic Sedan - 148k - Brothers (OC-155k)