I'll start with the car - Its a 2001 Windstar with the 6 cyl in it. It has about 140K on it

Now the problem..
Just recently (after the rain the other day) the car started running very rough, popping, and would stall out. After warming up for a while, it was drivable again. Stop for a few minutes, and problem comes back again.

The plugs are new, and possibly the wires. I was thinking about changing the coil pack, but it doesn't seem to be a miss. I was thinking, can the muffler be clogged maybe? The only cel on are for both o2 sensors, which were both done about a month ago. The cel light came back on after about 300 miles for o2 sensors.

If anyone has any idea of what to check, please let me know! Thanks

 

In addition - I have no CEL coming on when driving. Can barely hit 40 mph with the car. It has a sound almost to a bad exhaust leak, and gets a popping sounding like its coming through the intake. I havn't replaced the coil because if it was a miss, I would expect the cel to come on. Any ideas??