Knowing that the ECM uses (among other things) the MAP sensor's information based on vacuum changes to adjust for a lean or rich condition, could a MAP sensor that is going bad give incorrect info to the ECM and cause hesitation problems? For instance, when the throttle plates are closed vacuum is high. When the throttle plates are opened quickly while accelerating, vacuum drops significantly. Is it possible that a faulty MAP would not sense the sudden change and therefore keep the ECM from richening the fuel/air mixture needed for acceleration?

yes.

Sounds like you need a new map sensor.Do you have any codes poping up with a check engine light?

How do you know your MAP sensor is behaving incorrectly? Have you ran a "scan" on it?

Yes, a "weak" MAP sensor will affect things, but so will other sensors.

I had my MAP sensor off and it looked dirty inside the vacuum inlet, so I stuck a pin in the hole to try to clean some of the crap out and when I put it back in, the SES light came on and the car just kept wanting to die. I put the MAP sensor from my RS in my IROC and the SES light stayed off, and no trouble. So I went and got a new one yesterday. There is better throttle response now.

[This message has been edited by speedlvr (edited April 18, 2001).]

I guess you won't do that again.