What is the purpose of the map sensor? What exactly does it do? Manifold Absolute Pressure....means....? I am asking this because my car has an idle problem. When i have the vacuum lines hooked up properly the car smokes a rich black smoke. it also eats gas. When i have the lines switched a tad it makes my idle go to 3000 or 4000 rpms. but no black smoke. could this be my map sensor?

 

The MAP sensor tells the ECU the level of vacuum/boost in the throttle body. The ECU then uses this information along with engine speed and a couple of other signals to decide how long to open the injectors and also what the ignition timing should be.

Chris

 

I took my car to the shop, they said they hooked up all the lines right but, like i said it smokes like a pothead and a hemp rally. They say it runs fine...but when it idles it loads the injectors causing it to bellow out the black smoke when at take off. They said it might be my ecu but i seriously doubt that. also when i drive the car it seems like if i dont have just the corret rpms the car is really jerky and at low rpms it does the clutch hop (you know when some one who cant drive a stick tries to drive it and the car looks like it has switches) and keep in mind this is while its in motion. has any one else had this similar problem? again this is if the vacuum lines are in the "correct way". Also i replaced the map sensor and that dropped my rpms to 2400 instead of 2500 WOOHOO@@!!! HELP PLEASE!