X2... I'm with Richiehd. Your IAC(idle air control motor)valve may be sticking or defective, MAP may be bad, Throttle position sensor bad, intermitten harness connectors,...quite a few things or combinations could be the problem. With out reading the codes your just guessing. Not that the codes will tell you exactly whats wrong, but it will tell you what the computer says is the resulting symptom.
If the computer senses a low MAP value, it dosen't necessarily mean the MAP sensor is defective, it could be a loose hose going to the brake booster causing a vacuum leak. The codes can narrow down the fault, but don't always tell exactly whats the defective component.
Please forgive my spelling.