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The MAP is one of the main component sensor for the idling circuit and the stalling when it surges down is most probably caused by it.
The surging up should be due to excessive air going into the intake manifold and possible causes are
1. Dislodged vacumn hoses.
2. Faulty PCV valves.
3. Faulty IAC valve.
4. Insufficient coolant or clogged coolant hoses to IAC.
5. Leaking manifold gaskets.
6. Throttle body plate/valve not closing fully.
Friday, November 21st, 2008 AT 3:49 PM