yeah thats pretty much the only way you could run cold. Now running too cold and running too hot are both bad. If you vehicle doesnt get up to operating temp that will affect your ecu and its readout. Since most everything is electronic in cars these days, alot of the instruments used are based off of your engine's temp. Say for instance in a start-up situation. Your computer runs in what is called open loop. What that means in that for the first 20 mins or so you computer will open the injectors up about 30-45% to help the engine warm up quickly. This is usually noted but the high rpms when you first start the car. After that time it will switch to closed loop, running normally at a normal idle. So "running cold" will affect ur gas mileage because the computer is giving the engine more gas trying to warm it up on top of you hitting the accelerator during normal driving. Running rich or with too much fuel in the cylinders will not only affect your gas mileage as stated earlier, but it will mess with your emissions as well. My vote is to get that thermostat looked at as soon a possible, gas is too high for that...lol... LiveOne