good post. very good (what country or USA state?)
0F or 0C?? big difference, 0F is very very cold ,
is that true?
this is international forum so do use the F or C so everyone knows.
so i bet the engine coolant temperature is out of control
on frigid days.
I use a scan tool see this engine, coolant do same its bad
The scan tool shows ECT it must rises to 180F (or more) and hold.
if not you have 2 problems, (either) the thermostat is bad, as below graphic shows. or you need to block off 1/2 the radiator with cardboard, ask any one in Canada that or Alaska.
it say thermostat is bad.
you might notice the cars heater is weaker, or if its weak all the time. not.
here is a classic bad Thermostat, slow and low.
it never reaches 180F ever.
and was insanely slow... 20miles to get this .......
the blue line is ECT (engine coolant temp sensor)
http://www.fixkick.com/my96-16v/TP-MAF-VSS-ECT-FUEL.JPG
this is just 1 step. if the coolant is at 180F or more
then you have IAC/ISC issues. if RPM is 1200 HOT, and hot is really HOT. then the ECU idle controls are INOP !
this can be 2 things, Bad ISC/IAC or fueling way wrong.
I have no idea at all what engine you have what size and cylinder count
or TOY name /num for engine???????
so can not guess which fuel system , so i stop here.
if EFI is map based, all air leaks to the plenum cause fast idle.
but i can only guess engine type.
the IAC is a thermal fast idle device, if coolant is warm, its closed.
that leaves the ISC< to control hot idle, either valve can fail.
