Intermitant miss... then stalls when I slow

[95blackGsTurbo]

I was just driving around tonight and I stoped at a stop sign and before I got there my car stalled. So I tried starting it and it just cranked, I looked under the hood, nothing seemed wrong so I tried again and it started. Then driving down the highway all the sudden my tach would go from 2800 down to 2-2200 quick like it was missing. It would get worse and worse until the car stopped running when I slowed down, I went to pull over to try starting it and it started itself again. Didn't even have to turn the key. I did notice when I got home my battery reeked really bad like rotten eggs. Could this cause this miss/kill. I recently installed a starter on my car but it ran fine for a while before that. I got my battery in Oct. of 2003 so it shouldn't be going bad. Any idea's?? One more thing, I hooked a scan tool up to it and got a code P1400 and something about the Powertrain. Any Idea's?

 

[95blackGsTurbo]

I just did a little searching and the P1400 code says:

P1400 Manifold Differential Pressure Sensor circuit. Any input on what this is or how it affects my car.