Had this problem twice within 5 minutes of each other on the way to work, and then it stopped. The problem is that when I am rolling up to a stoplight and downshift into second for some engine braking at around 25mph (Manual Trans). When I put it into neutral around 10mph, the RPM's slowly go down and then the engine stalls. The odd thing is that the stalling is very smooth. The only reason I noticed it the first time is because I lost my steering pressure. It happened again stopping at another light, with the exact situation, smooth and not noticeable. The first time it stalled, I noticed that my gas gauge had dropped down by quite a lot, from about a quarter tank to an eighth. I'm thinking possibly a loose fuel pump connector or my idle control valve. Any suggestions? Before I get flamed, I am only a noob in high school so I am not as experienced as most of the regulars on here. 03 Base, 163,000mi.

Vacuum lines be a good place to start lookin had a very similar prob and had one lil line that went from the TB to just below it so it was bent all funny and was all cracked and barely on there, changed it out and hasnt happened again

Well I found the issue. Took the air box off on top of the throttle body and the inner metal ring that connects to the air intake had fallen off and was stuck sideways inside the box. It must have choked the engine out of air a few times and then moved enough to allow air in. Glad I found that before it happened again.