Ignition Diagnostics with Caspers Sensor Check tool...

So; I have been doing spring maintenance on my cars which have not been driven in a while. Had no trouble getting the engine started initially. It ran perfectly in the yard, and for about 2 miles. Then it misfired a time or two. About another two miles later, it started to break up badly and finally stalled. It would occasionally fire once or twice, or backfire but no further meaningful running.

After transporting the car home, I connected the Sensor Check tool between the harness and the ignition module. The instructions for the tool state that the LED's should be either off or on. In my case they were of varying brightness, but never fully "off."

The "cam" sync signal had a relatively large increase in intensity between the dim and bright state. It went from very dim, to fully on.

The "crank" signal LED was almost full brightness at all times, with a very small increase when the crank trigger ring was moved into the sensor.

To me, this looked like a resistive short in the sensors or harness. Unplugging the sensors did not cause the LED's to go fully off. With the module and sensors unplugged, the signal wires for both sensors tested good, with no resistive shorts to ground or other circuits.

At this time, with only the module connected (with the Sensor Check tool) but the Cam and Crank sensors unplugged - the Cam light was still on dimly; and the Crank light was on relatively bright.

I plugged in another spare module (with grounding jumper), and found out that the Cam light was much dimmer now, and the Crank light was barely visible. After installing this module, the engine would start and run well.

The module that stopped running was not marked with any maker's name. The spare I installed was a GM marked module. Both of these were Delco style with the 3 removable coils. Also I tried a Magnavox style unit and also saw some level of lighting from the Sensor Check tool, when the sensors were in the off state; however this one was much dimmer than either of the two Delco units.

So; my question is - has anyone else seen this sort of indication with the Sensor Check tool? I am concerned that the module I installed is beginning to develop the same problem that made the first one stop functioning. I tried to have one of these modules tested by a local parts place, and they don't have a tester for this one. They only can test the fast-start modules from the 3800 engines, or newer.

This tool is new to me and I am unfamiliar with it. The instructions were clear but they did not mention anything about varying brightness - only the LED's being off or on.

EDIT: I tried searching for info on this, but receive a server error and the search is not functioning.

Thanks sincerely for any idea.
One time I had the same issues and it was the MAF, just saying...
Thanks! Yeah I have had fits with those MAF's. This car actually has been converted to MAF-less operation.

The ignition module replacement did fix it. I'm just trying to figure out if the not-fully-off LED's on the sensor check tool are normal or not; and by extension whether or not the replacement ignition module is beginning to have the same failure as the old one.