Ruff idle problem

6000 LE 122K MILES. 3.1 ltr. I'm having a problem with the car not holding a good idle. Happens from cold start up to till it gets hot, and the car really needs to be warmed up good even then. I've tried turning up the idle a bit but that has no effect on it. I just replaced the fuel pressure regulator valve because fuel was pooring into the throttle body unregulated. Before I changed the valve I could't even keep a idle, it would konk out. But now, after the replacement, it will not konk out, but it still idles very ruff, in or out of gear. Any ideas on this problem would be appreciated.

Ok scratch that problem. Looks like I figured it out. There must be some sort of air intake to fuel ratio in the throttle body. Because I had turned up the idle some what to try to keep the engine running but the problem only got worse, with the engine rev'n up and down when I would coast in drive, it kinda chugged to a stop light. So I decided to try reverse scicology and turn the idle way down, it seems to work. There must be a fine line to having the proper idle set, to get the right amount of fuel to air ratio.