Idle not steady - moves up/down 150rpm

Help,

96 Lesabre - 115K - 3.8L - eng K
Just replaced the UIM and LIM cause I found the antifreeze under the UIM, job done. Still lifter ticking (cold only) but that is only one problem.
When the car is at idle in neutral (hot) the RPM is going up and down about 100 to 150. When in gear it levels out. I cleaned the Idle control valve pintle and EGR valve. Vacuum is good, plugs, and wires are AC only 1 month ago. I am getting a computer code of 306 and 1460. But those codes I think are coming when the car is started cold and the lifters are loud and the engine is missing. I put seafoam in today and will drain in a couple of days.
Could it be the fuel filter? that is old.
I also changed the #6 coil with one from my old 96 Transport, no change.
I think the idle problem can cause the 306 issue.
This car has many problems lately, i dont get it.
Another thing when I disconnected the battery for 1 hour the computer did not clear, the codes were there just after I reconnected the battery.
Talk to me! what else did I miss.

Check for vacuum leaks. Check the pcv valve it has a o-ring and the sensor housing on top of it has a bigger o-ring. That's what happened to mine. I left an o-ring out.

Help,

96 Lesabre - 115K - 3.8L - eng K
Just replaced the UIM and LIM cause I found the antifreeze under the UIM, job done. Still lifter ticking (cold only) but that is only one problem.
When the car is at idle in neutral (hot) the RPM is going up and down about 100 to 150. When in gear it levels out. I cleaned the Idle control valve pintle and EGR valve. Vacuum is good, plugs, and wires are AC only 1 month ago. I am getting a computer code of 306 and 1460. But those codes I think are coming when the car is started cold and the lifters are loud and the engine is missing. I put seafoam in today and will drain in a couple of days.
Could it be the fuel filter? that is old.
I also changed the #6 coil with one from my old 96 Transport, no change.
I think the idle problem can cause the 306 issue.
This car has many problems lately, i dont get it.
Another thing when I disconnected the battery for 1 hour the computer did not clear, the codes were there just after I reconnected the battery.
Talk to me! what else did I miss.

What happens when you take the oil cap off while the car's running? Do you get a lot air rushing in. That means the bottom o-ring is off the PCV.
http://i86.photobucket.com/albums/k110/imidazol97/95L36PCV-1.jpg
Here's a picture I found on the web.

I checked the vacuum and its in the green - normal zone.
Also checked the PVC and orings. These are all new since I just replaced the UIM and LIM.

Thx