A heuristic method of model choice for a nonlinear regression problem on real line, based on the Equation Finder (EF) of Zembowicz and Żytkow (1992), is proposed and discussed. In our implementations of the EF we use a new, actually a three-stage, procedure for stabilizing model selection. First, a set of pseudosamples is obtained from the original sample by resampling in some way. Second, for each pseudosample, a family of acceptable models is found by a clustering-like algorithm performed on models with largest (adjusted) coefficients of determination. And third, the final selection is made from among the models which appear most often in the families obtained in the second stage.