A method for operating an internal combustion engine is provided and at least a first map of prefixed first values is predetermined, each prefixed first value being a function of a prefixed nominal fuel quantity (Qecu—prefix). The method includes, but is not limited to the steps of determining a nominal fuel quantity (Qecu) for one injection, calculating an actual, torque forming, injected fuel quantity of the injection (QUEGO) and calculating at least one first parameter (Qdelta) which is related to the actual, torque forming, injected fuel quantity of the injection (QUEGO). After that, the nominal fuel quantity (Qecu) is modified according to the value of the at least one first parameter (Qdelta) so as to obtain a corrected fuel quantity (QecuCorr) that corresponds to the actual fuel quantity injected during the injection. The method further includes, but not limited to the step of comparing the corrected fuel quantity (QecuCorr) with each of the prefixed nominal fuel quantity (Qecu—prefix) and operating the engine using, from the first map, the first values which corresponds to the corrected fuel quantity (QecuCorr), according to the result of said comparison.