Stalling and Rough Idle

[ZoomGlide125]

I'm currently trying to bring back to life an abused 99 2.5 5 spd. When I first brought the car home it ran a little rough, a bit of a missfire down below 3500 RPM but it ran well enough to get home. The next morning when I went to fire it up the and the battery was dead. I replaced it later that day and when I started the car it ran incredibly poor. Would not idle, ran very very rough and would stall whenever the RPMs got low requiring constant throttle to keep running.

I just did basic tune up stuff on it now to see if it would fix the problem. New plugs, cleaned the throttle body, idle control valve, and MAF. This made the car run way better. It will idle after start up, but hunt for an RPM. It'll normally run pretty smooth around the high 700 RPM range for a hand full of seconds and then drop down and hunt around 3-500 RPM dipping low enough to dim the dash lights.

Normally the engine can rev up into the RPMs smoothly, occasionally though it will stumble a bit and maybe backfire. The other problem is that it will always stall with no load on after lifting off the throttle. If I catch it and slowly reduce the RPMs it will return to the rough idle. The car doesn't give any codes unless it backfires. When it has done that it threw the codes for backfires on cyl 1, 2, and 3. However that's not every time the car runs. I've checked a bunch of times to make sure I got all the vacuum connections back on and seated properly. I'm not familiar enough with the engine to know what sounds are normal for it but it dose sound like there is a bit of a sucking noise at idle that goes away when you start the step on the throttle.

I'm not sure where to look or what to test next.