I've spent many hours of trial and error over the years. Another option instead of a MAP Sensor Enhancer or EFIE is a HHO Chip. This is the one I use because it's easier to install an with about an 80% success rate.
Hydrogen Generator Dry Cell Stainless Steel HHO Dry Cell Generator
HHO DRY CELL KIT HYDROGEN GENERATOR Twin Dry Cells 4 Quart Tank
HHO Dry Cell Kit With Volo VP12 Chip Enhancer and 40 Amp PWM
HHO Generator, Hydrogen/Oxygen H2/O2 Separation Cell WSG12
HHO Generator, Hydrogen/Oxygen H2/02 Separation Cell WSG24
19 PLATE HHO HYDROGEN GENERATOR SEALED DRY CELL KIT. WATCH VIDEO
