Missing at low RPM, is timing light good for checking for consistent spark?

[smassey22180]

I was checking my timing yesterday and noticed that I am not getting a constant flash from the timing light. The engine runs a little rough and I figured it was bad gas (almost gone now) or needed a carb rebuild (was going to re-build if new gas did not fix).

If I put the timing light on the coil wire, the flashing pauses for a split second every 5 seconds or so. It is tough to tell with a 3.0 but the rough running seems to correspond. Cap, rotor and wires appear new. Plugs are new. Engine has a tough time running below 1000 rpm but runs great cruising.

Stupid question, but if the miss is caused by a fuel issue, would the timing light not flash for that stroke?

Thanks

 

[Don S]

Re: Missing at low RPM, is timing light good for checking for consistent spark?

When was the last full tuneup? Spark plugs, cap and rotor?
I would go there first. If the plug doesn't fire, then the timing light won't flash.
Use either AC or NGK spark plugs and see if it smooths out.