Can the ignition control module on a 1997 Chevy S-10 be tested on a testor , be passed as OK and still be failing when installed on the engine?

Truck would  start, but would not run when throttle was opened.  Replaced fuel pump, Pressure regulator,and filter.  It started right up, responded to throttle just fine, and I took it out for a test run.  2.5 miles down the road, it died and when I started it again, it would not accept throttle and died again. I started it again with the same results.  Towed it home, disconnected the fuel line at the filter, checked filter and fuel line for obstructions and found everything open.  Fuel pump comes on and engine starts but will not accept throttle.  apparently, something is interfering with the fuel pump continuing to run causing inadequet fuel pressure. Checked the pump relay, but the relay is fine. I suspect the ICM, so I had it tested.  I think the tester briefly indicated a failure but then moved on to the passed position.  Can the ICM be passed as OK and still fail when installed on the engine?