A bad MAP sensor can potentially cause all sorts of issues.
1. A rich or lean fuel mixture. You may notice a gas smell even after warm-up and/or pinging at random times or all the time or whenever.
2. Excessive fuel consumption (rich)
3. Rough idle
You will especially notice the hesitation off of idle when you first give it gas. The engine may even die if you don't give it enough gas off of idle.