YOUR MAP SENSOR IS GIVING A READING OF 24PSI AND WHAT IS YOUR BARO PRESS? SHOULD BE 13-18PSI. SUBTRACT THE BARO FROM THE MAP AND YOU WILL GET THE BOOST AROUND 8 - 15 PSI. ARE YOU HAVING A 478 CODE. THE BACK PRESSURE SENSOR TUBE MAY HAVE CARBON IN IT OR THE SEN... Login to read more.