Why is my 2002 highlander hard to start when it's cold outside?

There is a relay in the fuse box under the hood near the battery, it's marked MG/CL it controls the compressor clutch.

Perhaps the Avensis has a brittle cable like in the Highlander.
Please see
http://www.tundrasolutions.com/forums/highlander/32217-heater-quit-sort-of/
It's usually broken solder joints on a cable behind, and feeding, the temperature knob.
I repaired my 2002 Highlander yesterday thanks to this site.

SOUNDS LIKE U ARE DESCRIBING A TRANSMISSION BEARING. iT MAY EVEN BE A SMALL EXHAUST LEAK. MY ADVICE TO U IS, iTS NOT GONNA GET BETTER SO GET IT CHECKED OUT BY SOMEONE U TRUST. GOOD LUCK

Probably not. If one of the sensors were faulty you should have a check engine light on and a trouble code for the sensor.
Have you checked the plug wires ?
And as a side note, I don't show a 2002 Venture mini-van having a 3.8 engine.

NEED A BATTERY WITH MORE COLD CRANKING AMPS.

You might wish to check the diverter box to make sure that it's blowing the right air in the right places. Also, check the dash ductwork-they like to split.

removing air intake chamber , intake manifold, its hard

defective fuel pump, bad pressure regulator, or worn spark plugs are common problems

You have a broken wire on the heater control potentiometer. You can either order and replace the control, which is expensive, or you can remove the control, and disassemble it, and re-solder the broken wire. We do this all of the time; resolder the pots bacjk on to the main PC board.

I am having the same problem with a 2002 Highlander, V6. I have read in other posts that the Idle Control valve may be to blame. I took out the throttle body and cleaned it out thoroughly. Solved some of the problem but it will occasionally be difficult to start when cold and I drive a short trip. I plan on replacing the idle control valve in the near future. I found a temporary fix is to turn on the car and keep the idle up near 2000 rpm for about a minute (allows engine to circulate oil) and then rev up the engine to about 5000 rpm a few seconds at a time. I am then able to drive off with minimal problems.