I would not replace any injector yet. My van is over 193K miles and still running with original injectors. Normally, distributor problems in these vans cause erratic idle while stopped. Last time I had them, I replaced the distributor cap and rotor and that took care of the issue. My van was around 187K at that time, I replaced the original distributor cap. My van is still running with original distributor.
What I am saying is it is not necessary to start replacing parts LEFT and RIGHT, UP and DOWN to get your van in good working condition. Specially at relative low mileage.
The other problem that distributors will cause is the engine shuts down while driving. The vehicle does not want to start until the engine is cool. Then the engine starts again and shuts down again when hot. That is what others are reporting here and problem goes away by replacing the distributor.
What I could think is fuel pressure. At speeds of 65 mph you need good fuel supply. If the fuel delivery is not constant, I can picture some up/down in the engine’s performance. Think about the symptom you have to confirm if it could describe a fuel pressure problem including a possible dirty fuel filter.
Hope it helps.