Techron and Marvel Mystery Oil are two completely different chemistries. We recommend using Marvel Mystery Oil in the gas tank at every fill-up. This helps keep carbon deposits on fuel injectors softer and easier to remove. In addition, Marvel Mystery Oil helps replace the lost lubricity of the gasoline due to the additon of ethanol in the fuel.
Techron is designe to remove the hard, baked on carbon deposits that can build-up on fuel injectors. Techron has basically two formulations, one that is designed to remove these depsoits over a long period of driving and are intended to be added at each tank. The other Techron formulation is designed to be used about once every 3,000 miles and removes the carbon build-up in one tank of gas.
Our recommendation is to use Marvel Mystery Oil with every fill-up and then use a Techron type additive about every 3,000 to 5,000 miles. We have a product called Marvel Complete Fuel System Treatment, Stock No. MM02, which uses the same chemistry as Techron. Check with your auto parts store to see if he carries this product or can get it for you.