I changed my M.A.P. sensor in hopes it would help with my gas mileage but it didn't. What it appears to help with is the two to three second crank time that it takes to start my car, before the car is warmed up for the day. With the new sensor, my crank starting time is reduced to about one second. Just F.Y.I. :-)

 

Nice. I would not have thought the map sensor would help.

 

Don't know if it would help in every situation but it did in mine. It's a gamble I guess. :-) Here's the definition of what that sensor does so it seems it can be related to start time.
In fuel-injected automotive engines, a manifold absolute pressure (MAP) sensor is used to continuously monitor the amount of air flowing into the engine, so the computer can calculate air density, adjust the amount of fuel to spray into the combustion chamber and adjust the ignition timing.