I was on the dyno today with my car and this is what happened. It was in fourth starting the pull. When the car went to WOT the map reading went to 98.9 but through out the pull it decreased to 93.7. This occur from 3000 to 6300 rpm. It gradually decreased as rpms increased. What causes this to occur?

Michael

 

Restriction in the intake tract will cause these readings. Try running once with the filter off and see if the numbers change. As you go up in RPM's, the engine is calling for more air than can be supplied, which lowers the MAP reading. Have you cleaned or replaced your filter lately?