Yes, i disconnected neg. terminal when doing this. I unscrewed the sensor, and it seemed to me that there was plenty of vacuum pressure there.. how would i go about testing that though? i do not hear any air leaks anywhere near the sensor, the lines, or the charcoal canister.. The car started acting this way a couple days after i replaced the clutch... The idle goes up to 2500 as soon as i let off the clutch, and while i am driving, it feels like its at 2500 too, i do not have to give it gas when i start moving in 1st...... my mechanic said that the #5 engine light, MAP sensor usually does mean vac leak if the sensor is still good...