Dakota49 Dodge Dakota JOIN HERE 
6/01/2008 14:58:52
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Message: Pam, what that stands for is Manifold Absolute Pressure, actually it measures manifold vacuum. The only time you could, or would have any pressure is if you have some kind of turbo, or belt driven forced air device. And yes you should have vacuum at the MAP sensor at idle. If you have a vacuum gauge find a place to hook it up to the intake manifold and see what you have for vacuum. At idle warmed up you should have at least 16inches or more. If you open the throttle wide open it should drop to nothing, or near nothing.when you let off it should spike around 20-30 inches then come back down to were it was while idling. If you think you have a vacuum leak, there are a lot of vacuum lines that could cause problems so check them first before you decide its the manifold gasket, if you can't find a vacuum leak then it could be the manifold gasket.
How many miles do you have on the truck?
Good Luck
Dakota49
1988 3.9 4X4 5speed
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