I have a 1995 Dodge Ram 1500 with a 5.2 L V8. When facing the engine I know that the device to the right of the Throttle Body (TB) is the TPS, behind the TB is the IAC, but what is the device directly in front of the TB?? Can anyone tell me???
MAP (manifold absolute pressure) sensor
Thanks! What purpose does it serve? I have replaced the TPS and will be replacing the IAC to try to solve a problem that causes my truck to stall when idling. Except for idle, the truck runs very well.
Well.... it measures the absolute pressure in the manifold. :)
For the non-smart-ass answer - it's used by the computer to determine how much fuel to feed. By measuring the density of the air in the manifold, the computer knows how much air is entering the combustion chambers, and knows how much fuel to mix in to maintain a proper air:fuel ratio.
Problems with the MAP sensor usually will set a diagnostic code, and would be fairly far down on the list of possible things gone wrong when an engine won't hold idle. The IAC motor that you're looking at is a far more likely suspect.
Thanks again! I'll be changing out the IAC tomorrow.
I took your advice and cleaned the IAC and Throttle Body with throttle body cleaner and WOW it made a significant difference on how my truck idles!! Thanks.
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