Well, reading this
http://www.aa1car.com/library/misfire.htm almost tells me that adding techron is causing your injector to clog up :-) Realistically, I can't think of any explanation as to why Techron causes fuel related misfire in your vehicle.
This part of the article does not appear to have any association with Techron or its function...
If you find a P0300 random misfire code, it means the misfire is random and is moving around from cylinder to cylinder. The cause here would likely be something that upsets the engine's air/fuel mixture, such as a major vacuum leak, a leaky EGR valve or unusually low fuel pressure (weak pump or faulty pressure regulator).
