If you think you have bad coil and you have no multimeter a great test would be to keep your foot on the brake and accelerate. If engine stumble from that chances are your coil is bad! On HEI systems I have replaced coils only to find that and the entire distibutor and cap had to be replaced.
Hmmmm. I would rather test it or have it tested. Putting your foot on the brake and pressing the throttle could be a host of other problems. For instance running too lean would cause cut out also. Even aging spark plugs will misfire under a load like that. Spend the hundred bucks to have it diagnosed. Even if your fix the part yourself you can at least get back on the road to clean some more carpet.
I have never performed this test and had it be anything other than a bad coil. A bad coil can show a perfect idle and under load will cause severe misfire to the point where the engine almost stalls or does stall. On a cold engine and lean mixture is suspected the mixture would have to be so lean to create this type of misfire that running in ildle would also be rough. Same goes for bad plugs. Bad plugs would be evident at idle.
