My stock '87 is doing exactly the same stumble, but it is usually only on cold starts and manifests about two minutes after starting.  I usually get out of the neighborhood and then encounter the behavior, but it also happens if I just let the van idle in the driveway for that length of time.  No response to throttle variation while this is happening. Clears up almost immediately and does not reoccur on that day.  I'll be running some Techron through it before doing additional troubleshooting. I do keep Stabil in the tank. 
In fairness to the van, it is not a daily driver and can go weeks without being started.  What is wrong with my life for this to be the case?
Stephen 

     On Monday, June 15, 2015 10:25 AM, Rick Cooper <rickdcooper@GMAIL.COM> wrote:
   

 I've noticed that when accelerating from an intersection, after sitting at
a red light, my 2.1 WBX will sometimes hesitate for 5 to 15 seconds.  I'll
start moving, but the engine has no power and giving it more gas does
nothing.  After those few seconds, the engine will start to pick up power
and soon everything will be running fine.

This has just start happening and is still sporadic, but it is becoming
more frequent.  Seems to only happen after a full stop, like at a red
light.  Would this be a clogged fuel filter or what?

Thanks for any ideas.  FWIW,  the fuel tank and the ECU were replaced a few
years ago.

Rick