Inspect the rubber nipple (fitting) from the MAP sensor to the throttle body. Repair as necessary.
CAUTION: When testing the MAP sensor, be sure that the harness wires are not damaged by the test meter probes.
Test the MAP sensor output voltage at the MAP sensor connector terminal B. With the ignition switch ON, and the engine OFF. Output voltage should be 4 to 5 volts.
Test the MAP sensor output voltage at the MAP sensor connector terminal B at a hot, neutral idle speed condition. The voltage should drop to 1.5 to 2.1 volts.
Test MAP sensor supply voltage at sensor connector terminal C with the ignition ON. The voltage should be approximately 5 volts.