How to make your own performance chip for your car?

remove your factory air intake temperature sensor,  let it settle to room temperature (68-72F) and take a resistance reading. Purchase a 1/2 watt resistor of this value and put one lead into each of the sensors two plug leads. Don't let the leads short together, no damage will result but it will short the reading to 0 ohms. Electrical tape it and leave the factory sensor in place. That's how they build "jet" chips and all the others out there. Expect the same lack of results. This tells you computer that the air coming in is about 70 degrees no matter what. try readings at colder temps 60 and 50. At some point your computer will adjust the timing for the colder air resulting in the gain they promise.