: Map sensor

05-12-05, 12:42 AM
Now if the map sensor is bad is there a way to test it or just go out and get a new one? cause when you are driving it it will shut off and stall and sometimes in the morning when you go to start it it wont start it takes a while for it to start! like it will idle up and then down and up and down again and you must shut it off and start it up again! the PO32 code will come up and say current and then sometimes say history? would the map sensor be makeing all these problems possible? and plus its been getting bad gas mileage cause of all this i really need help on this and cant find the answer the check engine like is on and runs fine at times dont know if its map sensor or maybe vacum leak? what can is possile be?

05-12-05, 01:03 PM
It sounds like a vacuum leak or a bad idle air control. Your car might have the idle speed control motor that opens the throttle blade a tiny bit to control idle speed. The idle air control works a little differently and bypasses the blade with a variable-width opening controlled by a solenoid. Whichever it is, it sounds like that's the problem if the idle changes all the time. If you hear hissing at idle, that could be a vacuum leak to be fixed. Maybe a hole in a hose or a fitting broken or something. The MAP wouldn't cause the idle problem you're having, or at least I don't understand how it would do that, but it should be fixed nonetheless. I think a MAP sensor issue is pretty much check the wiring and if that's good, just replace the sensor.

05-12-05, 07:40 PM
The answer hasn't changed since the last post. If it is setting the code for the MAP sensor then the MAP sensor or wiring leading to is is damaged or failing.

Follow the bundle of wires from the intake manifold (just beside the throttle body) and see if it is damaged or burned or cut or something. If no problems are seen then likely it is the MAP sensor itself.

If the MAP sensor is failed as the code would indicate then that would cause the problems you describe. The MAP sensor is located under the cover of the intake manifold. Take the perimeter row of screws out of the silver top cover and remove the top cover. The 4 inner bolts that are recessed into the cover do not need to be removed to remove the cover. The MAP sensor is the small rectangular box that is about the size of a tictac box near the throttle body end.

This does not sound like a vacuum leak or problem with the idle speed control. The idle speed control motor may be failing or the closed throttle switch inside the idle speed control motor may be bad also but an idle speed control motor is not going to cause the code for the MAP sensor.

I would say a good guess is to replace the MAP sensor as described.

The MAP sensor is what provides the engine controller with basic information regarding airflow thru the engine for computing the fuel delivery. If the MAP sensor is acting up the fuel delivery will be totally screwed up and idle quality and basic engine operation will be affected. There is no way around the engine needing the MAP sensor to operate correctly.