Is the 5-second stalling occuring across all 4 cylinders or only 2 cylinders?

How long does it run smoothly before the next 5-second stalling?

Does it do it when sitting in the driveway idling, or only on the road? Or both?

Is it worse under heavy throttle load or the same as when cruising light footed?

Have you cleaned the throttle position switch contacts?

Have you tried attaching a timing light to the various plug wires to see if could be an ignition problem?