As previously reported in this thread, the engine stumble can be caused by the PCV hose from the rear of the intake manifold. This is a Motorcraft hose that is apparently only available from your local dealer with convenient hours. However for those of us who can't seem to be off in the middle of the M-F 8-4 timeframe here is a fix that seems to work and costs about $20.
First remove the offending hose (Motorcraft P/N C013A 988F-6N664-BA) and hold onto it. The hose clamp can be released by slipping a set of needle nose pliers into the two raised areas on the clamp and prying back until the clamp pops loose and you drop the needle nose into the engine compartment. The hose can then be removed by pulling and twisting.
Remove the opposite end of the hose with the aid of a long screw driver prying gently against the end of the hose.
Now take the hose to your local auto parts store and ask them for a replacement. They won't have it. So follow this up by asking if you can see all their hoses and match it up to one that is close in shape and size. They will invite you back to a wall of hoses and after looking for 10 minutes, you won't find it.
Now go to the wall of HELP! parts. These are parts that DORMAN has packaged to help you fix things that no one has parts for. Pick out P/N 46017 a PCV END Assembly. This part is 5/8" id on one end and elbows down to 3/8" id on the other. PERFECT. However it is about 1 1/2" long, so go over to the fuel line hose and cut 2 feet of 3/8" id hose. You only need one foot, but it's always good to have too much.
Now find the obscure area in the store where they sell VACU-TITE hose connectors and buy PN 47348 3/8" by 3/8" barbed straight hose connector. For the non US crowd that is 9,52 mm x 9,52 mm.
On the way out, buy a couple of hose clamps with a 5/16" to 7/8" range. You will buy a pack of 4 even though you only need one, then when you get home you'll find 3 of them that you still have from the last time you bought a 4 pack.
Now it's time to assemble. Insert the hose connector into the 3/8" side of the PCV END ASSEMBLY and then insert the other end of the connector into the 2 Ft. length of 3/8" fuel line. You may want to use some black electrical tape to wrap the connection.
A little white lithium grease on all the hose nipples makes everything slippery so it is easy to attach the hoses.
Trial fit the assembly and then cut the 3/8" fuel line hose down to the length that provides a large radius and keeps the hose from contacting any engine parts. For me this was about 13" long (12" would also work, but what the hell, I had a whole other foot to play with).
Now slip the 5/8" ID end of the PCV END ASSEMBLY over the hose nipple on the manifold, remembering to put a hose clamp over the end. Slide hose clamp in place and tighten. Not too tight, not too loose. Just right.
Now slip the other end (3/8" ID in case you get confused) onto the other hose nipple. Apparently this end doesn't require a clamp.
Only one thing left to do. Pull all the power fuses to reset the ECM. Fuses number 1 and 7 in the engine compartment fuse box on the 2000 SE seemed to work.
Now start the car and sit inside and revel in the glow of success and smooth idling.