Assume for a moment that I want to verify the correct plugs are in the correct sockets. There are different spark plugs for each of the 3 cylinders on the Insight. Are there etchings on the engine telling me which ones go where? Also, what are the physical differences in the plugs that actually make the diference? I am going to check mine, for lack of Oomph and I want to be sure everything is as it should be.