1995 Trans Sport rpm problem

New to me vehicle. Just replaced muffler, changed oil and spark plug wires. Will rev to 4000 rpm and motor quits. At 3000 rpm motor restarts and runs up to 4000 and quits again. Holding throttle in same position, repeats this process over and over.

When you say quits, what exactly happens? Does it stumble? Or is it like you turned off the engine? It almost sounds like a rev limiter or fuel cutoff. Does it do this just idling or under a load/driving?

When you say quits, what exactly happens? Does it stumble? Or is it like you turned off the engine? It almost sounds like a rev limiter or fuel cutoff. Does it do this just idling or under a load/driving?
without a load, don't know about driving. Haven't gotten to that point yet. The engine has no exhaust sounds, but the instruments are all still working, so I assume either a fuel shutoff or a governor of some type. The engine cuts out until 3000 rpm and then starts up again until 4000.
doesn't sound or act like an electrical shutoff. Just no engine noise.